Evaluate the value of sin 90° + Cos 90°. Find the value of 2sin 90° – sec 90° What is the value of (sin 90°)/2 – sin 30°? Keep visiting BYJU’S for more information on trigonometric ratios and its related articles, and also watch the videos to clarify the doubts.Explanation: using the addition formula for cos. ∙ xcos(x −y) = cosxcosy + sinxsiny. cos(θ − 90) = cosθcos90 + sinθsin90. = cosθ(0) +sinθ(1) = sinθ. Answer link.Study with Quizlet and memorize flashcards containing terms like Sin 90°, Cos 90°, Tan 90° and more. Fresh features from the #1 AI-enhanced learning platform. ... To calculate cosine of 90, enter cos(90), after calculation, the restults 0 is returned. Calculate the cosine of an angle in gradians . To calculate the cosine of an angle in gradians, you must first select the desired unit by clicking on the options button calculation module. After that, you can start your calculus.Explanation: using the addition formula for cos. ∙ xcos(x −y) = cosxcosy + sinxsiny. cos(θ − 90) = cosθcos90 + sinθsin90. = cosθ(0) +sinθ(1) = sinθ. Answer link.Tabel Trigonometri Untuk Seluruh Sudut. Jika tabel diatas menjelaskan cara menghitung sin cos tan dengan tabel trigonometri sudut istimewa yakni sudut sudut istimewa seperti 0°, 30°, 45°, 60°, dan 90° sehingga akan membantu kalian menghafal dengan cepat nilai sin cos tan dari tabel trigonometri diatas, maka disini akan dijelaskan secara ...Tangent 90 degrees is evaluated as undefined because tan of an angle is equal to the ratio of sin and cos of same angle. Since, sin 90 = 1 and cos 90 = 0, therefore; Tan 90 = sin 90/cos 90. = 1/0. = ∞. As we have got the result as infinity, and we cannot define infinity, therefore tan 90 is undefined.The formula for converting degrees into radians is given as, Radians = Degrees × π 180 ∘. Thus, in order to calculate the value of Cos 90 in radians, we need to multiply it by the fraction of π 180 ∘. Value of Cos 90 in radians = value of tan 90 in decimals × π 180 ∘. Value of tan 90 in radians = 0 × π 180 ∘.The ratios of the sides of a right triangle are called trigonometric ratios. Three common trigonometric ratios are the sine (sin), cosine (cos), and tangent (tan). These are defined for acute angle A A below: In these definitions, the terms opposite, adjacent, and hypotenuse refer to the lengths of the sides. In a right triangle, one angle measures x°, where sin x°=4/5, the cos (90°-x°) is: cos (90 - x) = sin x = 4/5. here, we have, we know that, cos(90 - x) = sin x. 90 -x lies in the first quadrant, in the first quadrant all are positive. Given : sin x = 4/5. cos(90 - x) = sinx. cos (90 - x) = sin x = 4/5For cos 170 degrees, the angle 170° lies between 90° and 180° (Second Quadrant). Since cosine function is negative in the second quadrant, thus cos 170° value = -0.9848077. . . Since cosine function is negative in the second quadrant, thus cos 170° value = -0.9848077. . . In a right-angled triangle, the sum of the two acute angles is a right angle, that is, 90° or π / 2 radians. Therefore and represent the same ratio, and thus are equal. This identity and analogous relationships between the other trigonometric functions are summarized in the following table. Reason Behind Cos 90 Not Equal to Zero (0) in Excel. 3 Simple Steps to Return Cos 90 as Zero (0) in Excel. Step 1: Convert Degree to Radians. Step 2: Find Out Value of Cos 90 in Excel. Step 3: Combine ROUND, COS, and RADIANS Functions to Return Correct Value of Cos 90. Things to Remember.In mathematics, the trigonometric functions (also called circular functions, angle functions or goniometric functions [1] [2]) are real functions which relate an angle of a right-angled triangle to ratios of two side lengths.VDOM DHTML tml>. What is the value of cos (90)? - Quora. Something went wrong. Những bài toán phổ biến. Lượng giác. Tìm Giá Trị Chính Xác cos (90 độ ) cos (90°) cos ( 90 °) Giá trị chính xác của cos(90°) cos ( 90 °) là 0 0. 0 0. Jan 30, 2018 · Here we use the formula of cos(A-B)=cos A cos B -sin A sin B. And on using this formula,we will get. cos(90-b)= cos 90 cos b + sin 90 sin b . Value of cos 90 = 0 and sin 90 =1 , And on using these values, we will get . cos(90-b) = (0) cos (b) + (1) sin (b) cos(90-b) = 0 + sin (b) cos(90-b) =sin(b) As we see that on using the formula, we are ... Sep 18, 2016 · Explanation: We will use the following Expansion Formula : cos(A −B) = cosAcosB + sinAsinB. Let A = 90∘, and = a. Therefore. cos(90∘ −a) = cos90∘ cosa + sin90∘ sina. Here, we have, cos90∘ = 0,sin90∘ = 1. ∴ cos(90∘ − a) = sina. Answer link. What is a basic trigonometric equation? A basic trigonometric equation has the form sin (x)=a, cos (x)=a, tan (x)=a, cot (x)=a. How to convert radians to degrees? The formula to convert radians to degrees: degrees = radians * 180 / π. What is cotangent equal to?Saiba mais sobre a relação entre o seno e o cosseno de ângulos complementares (ângulos que juntos somam 90°). Queremos demonstrar que o seno de um ângulo é igual ao cosseno de seu complementar. \operatorname {sen} (\theta) = \cos (90^\circ-\theta) sen(θ) = cos(90∘ −θ) [Não acredito. Por favor, mostre-me um exemplo.]Calculadora de coseno. Para calcular cos (x) en la calculadora: Ingrese el ángulo de entrada. Seleccione el tipo de ángulo de grados (°) o radianes (rad) en el cuadro combinado. Presione el botón = para calcular el resultado.Value of cos 180 degrees can be obtained with the help of unit circle and trigonometric sin and cos functions from other angles like 0, 90, and 270 degrees. Learn cosine pi (π) value with derivation at BYJU'S. Tangent 90 degrees is evaluated as undefined because tan of an angle is equal to the ratio of sin and cos of same angle. Since, sin 90 = 1 and cos 90 = 0, therefore; Tan 90 = sin 90/cos 90. = 1/0. = ∞. As we have got the result as infinity, and we cannot define infinity, therefore tan 90 is undefined. What is a basic trigonometric equation? A basic trigonometric equation has the form sin (x)=a, cos (x)=a, tan (x)=a, cot (x)=a. How to convert radians to degrees? The formula to convert radians to degrees: degrees = radians * 180 / π. What is cotangent equal to? cos 60° = √ (1/4) = 1/2. cos 90° = √ (0/4) = 0. Since, we know the sin and cos value of the standard angles from the trigonometrical ratios table; therefore we can easily find the values of the other trigonometrical ratios of the standard angles. The tangent of the standard angles 0°, 30°, 45°, 60° and 90°: tan 0° = 0. tan 30 ...An interesting trigonometry problem -- featuring roots of unity. YouTube Basic trigonometry | Basic trigonometry | Trigonometry | Khan Academy YouTube More Videos (sin(x))2 ⋅ ((cot(x))2 + 1) cos(π) tan(x) cos(3x + π) = 0.5 cot(x)sec(x) sin(x)Table 1.9 shows the values of sine and cosine at the major angles in the first quadrant. From this table, we can determine the values of sine and cosine at the corresponding angles in the other quadrants. The values of the other trigonometric functions are calculated easily from the values of sin θ sin θ and cos θ. cos θ.cos(A)=b/c -----> The cosine of angle A is equal to divide the adjacent side to angle A by the hypotenuse. we have that. sin(B)=cos(A) Remember that. A+B=90° -----> by complementary angles. so. A=90°-B. therefore. sin(B)=cos(A) sin(B)=cos(90°-B)Jun 17, 2018 · Explanation: using the addition formula for cos. ∙ xcos(x −y) = cosxcosy + sinxsiny. cos(θ − 90) = cosθcos90 + sinθsin90. = cosθ(0) +sinθ(1) = sinθ. Answer link. We would like to show you a description here but the site won’t allow us.In trigonometrical ratios of angles (90° - θ) we will find the relation between all six trigonometrical ratios. Let a rotating line OA rotates about O in the anti-clockwise direction, from initial position to ending position makes an angle ∠XOA = θ. Now a point C is taken on OA and draw CD perpendicular to OX or OX'.For cos 170 degrees, the angle 170° lies between 90° and 180° (Second Quadrant). Since cosine function is negative in the second quadrant, thus cos 170° value = -0.9848077. . . Since cosine function is negative in the second quadrant, thus cos 170° value = -0.9848077. . . What is COS 90 in Radians & Degrees? You can check the values from the table below: Cosine Trigonometric Ratios Table The values for Cos and Sin can be derived from each other as: Sin 0 = Cos 90 Sin 30 = Cos 60 Sin 45 = Cos 45 Sin 60 = Cos 30Free math problem solver answers your algebra, geometry, trigonometry, calculus, and statistics homework questions with step-by-step explanations, just like a math tutor.Similar Problems from Web Search. sin(90−θ)= cos(θ) because: sin(α−β)= sin(α)cos(β)−cos(α)sin(β) How do you find the area of one petal of r = 6sin2θ ? 29π Explanation: Area in polar coordinates is given by: A= ∫ αβ 21r2 dθ The first step is to plot ... How do you find the value of sin20(θ) using the double angle identity? VDOM DHTML tml>. What is the value of cos (90)? - Quora. Something went wrong. Cot ( 90 – θ) = Tan θ; Sec (90 – θ) = Csc θ; Csc (90 – θ) = Sec θ; Trigonometric Identities of Supplementary Angles. Two angles are supplementary if their sum is equal to 90 degrees. Similarly, when we can learn here the trigonometric identities for supplementary angles. sin (180°- θ) = sinθ; cos (180°- θ) = -cos θThe cosine function is an even function because cos (− θ) = cos θ. cos (− θ) = cos θ. For example, consider corresponding inputs π 4 π 4 and − π 4. − π 4. The output of cos (π 4) cos (π 4) is the same as the output of cos (− π 4). cos (− π 4). Thus,We would like to show you a description here but the site won’t allow us. What is sin (90 - A) cos (90 - A) equal to? You are here Question 1 Deleted for CBSE Board 2024 Exams. Question 1 (i) Deleted for CBSE Board 2024 Exams. Question 2 (i) Important Deleted for CBSE Board 2024 ExamsTo calculate cosine of 90, enter cos(90), after calculation, the restults 0 is returned. Calculate the cosine of an angle in gradians . To calculate the cosine of an angle in gradians, you must first select the desired unit by clicking on the options button calculation module. After that, you can start your calculus. Note that the image below is only for x in Q1 (the first quadrant). If you wish you should be able to draw it with x in any quadrant. Definition of sin(x) (side opposite angle x)//(hypotenuse) Definition of cos(90^@ -x) (side adjacent to angle (90^@-x))//(hypotenuse) but (side opposite angle x) = (side adjacent to angle (90^@-x) Therefore sin(x) = cos(90^@ -x) Similarly cos(x) = sin(90^@ - x)Online cosine calculator. Accepts values in radians and in degrees. Free online cosine calculator. cos(x) calculator. Tangent 90 degrees is evaluated as undefined because tan of an angle is equal to the ratio of sin and cos of same angle. Since, sin 90 = 1 and cos 90 = 0, therefore; Tan 90 = sin 90/cos 90. = 1/0. = ∞. As we have got the result as infinity, and we cannot define infinity, therefore tan 90 is undefined. An interesting trigonometry problem -- featuring roots of unity. YouTube Basic trigonometry | Basic trigonometry | Trigonometry | Khan Academy YouTube More Videos (sin(x))2 ⋅ ((cot(x))2 + 1) cos(π) tan(x) cos(3x + π) = 0.5 cot(x)sec(x) sin(x)Free math problem solver answers your trigonometry homework questions with step-by-step explanations. Cosine of 90° You may be somewhat fuzzy about how the cosine function behaves. Rather than memorize abstract stuff, visualize the unit circle with its radius projected onto the x-axis. From the picture, the cosine of 0° = 1.0, the cosine of 30° = 0.866, the cosine of 45° = 0.707, the cosine of 60° = 0.500, Calculadora de coseno. Para calcular cos (x) en la calculadora: Ingrese el ángulo de entrada. Seleccione el tipo de ángulo de grados (°) o radianes (rad) en el cuadro combinado. Presione el botón = para calcular el resultado. Jun 22, 2023 · Davneet Singh has done his B.Tech from Indian Institute of Technology, Kanpur. He has been teaching from the past 13 years. He provides courses for Maths, Science, Social Science, Physics, Chemistry, Computer Science at Teachoo. What is a basic trigonometric equation? A basic trigonometric equation has the form sin (x)=a, cos (x)=a, tan (x)=a, cot (x)=a. How to convert radians to degrees? The formula to convert radians to degrees: degrees = radians * 180 / π. What is cotangent equal to? cos(90° - 90°) = cos 0°-cos(90° + 90°) = -cos 180° Sin 90 Degrees Using Unit Circle. To find the value of sin 90 degrees using the unit circle: Rotate ‘r’ anticlockwise to form a 90° angle with the positive x-axis. The sin of 90 degrees equals the y-coordinate(1) of the point of intersection (0, 1) of unit circle and r.VDOM DHTML tml>. What is the value of cos (90)? - Quora. Something went wrong. Evaluate cos (90° + θ \theta θ). Step 1. Notice that 90° + θ \theta θ is in quadrant 2 (see graph of quadrants above). Step 2. Also notice that since we are dealing with 90°, we have to convert the cosine function to sine based on the rules of conversion listed above. Step 3.May 29, 2023 · cos 90° = sin 0° = 0 So, for cos, it will be like 1, √3/2, 1/√2, 1/2, 0 -ad- For tan We know that tan θ = sin θ /cos θ So, it will be tan 0° = sin 0° / cos 0° = 0/1 = 0 tan 30° = sin 30° / cos 30° = (1/2)/ (√3/2) = 1/√3 tan 45° = sin 45° / cos 45° = (1/√2)/ (1/√2) = 1 tan 60° = sin 60° / cos 60° = (√3/2) / (1/2 ... We would like to show you a description here but the site won’t allow us. In Python, math module contains a number of mathematical operations, which can be performed with ease using the module. math.cos () function returns the cosine of value passed as argument. The value passed in this function should be in radians. Syntax: math.cos (x) Parameter: x : value to be passed to cos () Returns: Returns the cosine of value ...Because cos () is a static method of Math, you always use it as Math.cos (), rather than as a method of a Math object you created ( Math is not a constructor).Tangent 90 degrees is evaluated as undefined because tan of an angle is equal to the ratio of sin and cos of same angle. Since, sin 90 = 1 and cos 90 = 0, therefore; Tan 90 = sin 90/cos 90. = 1/0. = ∞. As we have got the result as infinity, and we cannot define infinity, therefore tan 90 is undefined. Apr 28, 2022 · On the unit circle at 90 degrees the 90 degrees in radians is pi/2 and the coordinates for this are: (0,1). The tan function = sin/cos. In the coordinate system x is cos and y is sin. Therefore (0,1) ; cos=0, & sin=1 . Tan=sin/cos so tan of 90 degrees = 1/0. The answer of tan (90) = undefined. There can not be a 0 in the denominator, because ... Since cos(α) = b/c, from this definition it follows that the cosine of any angle is always less than or equal to one, and it can take negative values. The cosine of a 90-degree angle is equal to zero, since in order to calculate it we would need a triangle with two 90-degree angles, which is the definition of a straight line.Since cos(α) = b/c, from this definition it follows that the cosine of any angle is always less than or equal to one, and it can take negative values. The cosine of a 90-degree angle is equal to zero, since in order to calculate it we would need a triangle with two 90-degree angles, which is the definition of a straight line.Apply the reference angle by finding the angle with equivalent trig values in the first quadrant. Make the expression negative because cosine is negative in the third quadrant. −cos(90) - cos ( 90) The exact value of cos(90) cos ( 90) is 0 0. −0 - 0. Multiply −1 - 1 by 0 0. 0 0.To calculate cosine of 90, enter cos(90), after calculation, the restults 0 is returned. Calculate the cosine of an angle in gradians . To calculate the cosine of an angle in gradians, you must first select the desired unit by clicking on the options button calculation module. After that, you can start your calculus. Table 1.9 shows the values of sine and cosine at the major angles in the first quadrant. From this table, we can determine the values of sine and cosine at the corresponding angles in the other quadrants. The values of the other trigonometric functions are calculated easily from the values of sin θ sin θ and cos θ. cos θ. cos(90° - 90°) = cos 0°-cos(90° + 90°) = -cos 180° Sin 90 Degrees Using Unit Circle. To find the value of sin 90 degrees using the unit circle: Rotate ‘r’ anticlockwise to form a 90° angle with the positive x-axis. The sin of 90 degrees equals the y-coordinate(1) of the point of intersection (0, 1) of unit circle and r.In trigonometry formulas, we will learn all the basic formulas based on trigonometry ratios (sin,cos, tan) and identities as per Class 10, 11 and 12 syllabi. Also, find the downloadable PDF of trigonometric formulas at BYJU'S.May 10, 2015 · Cos 135° is an angle in the second quadrant. In the second quadrant, cos is negative. cosθ = x r. cos135 = cos(180 − 45) = −cos45°. An angle of 45° is found in a right-angled triangle of sides 1:1:√2. cos45° = 1 √2. ∴ cos135° = −cos45° = − 1 √2. Note that √2 is an irrational number and cannot be given as an exact decimal. In trigonometrical ratios of angles (90° - θ) we will find the relation between all six trigonometrical ratios. Let a rotating line OA rotates about O in the anti-clockwise direction, from initial position to ending position makes an angle ∠XOA = θ. Now a point C is taken on OA and draw CD perpendicular to OX or OX'. Cos 135° is an angle in the second quadrant. In the second quadrant, cos is negative. cosθ = x r. cos135 = cos(180 − 45) = −cos45°. An angle of 45° is found in a right-angled triangle of sides 1:1:√2. cos45° = 1 √2. ∴ cos135° = −cos45° = − 1 √2. Note that √2 is an irrational number and cannot be given as an exact decimal.The ratios of the sides of a right triangle are called trigonometric ratios. Three common trigonometric ratios are the sine (sin), cosine (cos), and tangent (tan). These are defined for acute angle A A below: In these definitions, the terms opposite, adjacent, and hypotenuse refer to the lengths of the sides.Interrogée par: Tristan Verdier | Dernière mise à jour: 29. Oktober 2022. Notation: 4.3 sur 5 ( 27 évaluations ) cos 12° 0,978 ; cos 20° 0,94 ; cos 45° 0,707 ; cos 60° = 0,5 cos 90° = 0 ; cos 0° = 1. Demande de suppression de source | Afficher la réponse complète sur maths-et-tiques.fr.Learn to find the sine, cosine, and tangent of 45-45-90 triangles and also 30-60-90 triangles. Until now, we have used the calculator to evaluate the sine, cosine, and tangent of an angle. However, it is possible to evaluate the trig functions for certain angles without using a calculator.The formula for converting degrees into radians is given as, Radians = Degrees × π 180 ∘. Thus, in order to calculate the value of Cos 90 in radians, we need to multiply it by the fraction of π 180 ∘. Value of Cos 90 in radians = value of tan 90 in decimals × π 180 ∘. Value of tan 90 in radians = 0 × π 180 ∘.Online cosine calculator. Accepts values in radians and in degrees. Free online cosine calculator. cos(x) calculator.We would like to show you a description here but the site won’t allow us.Jun 22, 2023 · Davneet Singh has done his B.Tech from Indian Institute of Technology, Kanpur. He has been teaching from the past 13 years. He provides courses for Maths, Science, Social Science, Physics, Chemistry, Computer Science at Teachoo. 사인 & 여각의 코사인의 관계에 대해 배워 봅시다. 여각은 서로 더하면 90°가 되는 각을 뜻합니다. 어떤 각의 사인값과 여각의 코사인값이 같다는 것을 증명하고자 합니다. \sin (\theta) = \cos (90^\circ-\theta) sin(θ) = cos(90∘ −θ) [무슨 말인지 모르겠어요. 예를 들어 ... Jul 31, 2019 · $$\sin(90°+θ) = +\cos(θ)$$ $$\cos(90°+θ) = -\sin(θ)$$ The source of the formula. I understand how to reduce angels that fall into the $2^{nd}$ , $3^{rd}$ , and $4^{th}$ quadrants to be expressed in the $1^{st}$ quadrant at $180°$ and $360°$ differences but not at $90°$ .
Cos 90 degrees is an important function used to find the solution of different trigonometric problems. However the first step is to be familiar with cos 90 degrees which includes how to represent cos 90 in terms of other trigonometric functions and trigonometric identities. Below are the following trigonometric identities which can represent .... 1 855 341 0049
Free Pre-Algebra, Algebra, Trigonometry, Calculus, Geometry, Statistics and Chemistry calculators step-by-stepWhat is sin (90 - A) cos (90 - A) equal to? You are here Question 1 Deleted for CBSE Board 2024 Exams. Question 1 (i) Deleted for CBSE Board 2024 Exams. Question 2 (i) Important Deleted for CBSE Board 2024 ExamsFeb 17, 2017 · cos 90 degrees = 0. The cos of 90 degrees is 0, the same as cos of 90 degrees in radians. To obtain 90 degrees in radian multiply 90° by π / 180° = 1/2 π. Cos 90degrees = cos (1/2 × π). Our results of cos90° have been rounded to five decimal places. If you want cosine 90° with higher accuracy, then use the calculator below; our tool ... MECANICO2015. el coseno de 90° = 0. para que te recuerdes te doy el siguiente tip que me explico mi papá y me sirve muchisimo: dibuja una circunferencia y ubica en ella los cuadrantes, en cada extremo empezando de derecha a izquierda desde el eje de las abscisas positivas y en sentido antihorario, ubica los puntos (1,0) , (0,1), (-1,0), (0,-1 ...Sine and cosine are cofunctions of each other. The cosine of 90-x should be the same as the sine of x. This implies that graph of sine function is the same as shifting the graph of the cosine function 90 degrees to the right. Graphic Representations related to cos (90-x)=sin (x)In mathematics, the trigonometric functions (also called circular functions, angle functions or goniometric functions [1] [2]) are real functions which relate an angle of a right-angled triangle to ratios of two side lengths.What is a basic trigonometric equation? A basic trigonometric equation has the form sin (x)=a, cos (x)=a, tan (x)=a, cot (x)=a. How to convert radians to degrees? The formula to convert radians to degrees: degrees = radians * 180 / π. What is cotangent equal to?The output of . Math.cos(90 * Math.PI/180) is. 6.123031769111886e-17 Notice the e-17 at the end, which means that this number is 6.123 x 10-17.This is a number so vanishingly close to 0 that it's effectively 0.Jun 22, 2023 · Davneet Singh has done his B.Tech from Indian Institute of Technology, Kanpur. He has been teaching from the past 13 years. He provides courses for Maths, Science, Social Science, Physics, Chemistry, Computer Science at Teachoo. Cos 90 degrees is an important function used to find the solution of different trigonometric problems. However the first step is to be familiar with cos 90 degrees which includes how to represent cos 90 in terms of other trigonometric functions and trigonometric identities. Below are the following trigonometric identities which can represent ...The sine and cosine of an acute angle are defined in the context of a right triangle: for the specified angle, its sine is the ratio of the length of the side that is opposite that angle to the length of the longest side of the triangle (the hypotenuse ), and the cosine is the ratio of the length of the adjacent leg to that of the hypotenuse. cos(A)=b/c -----> The cosine of angle A is equal to divide the adjacent side to angle A by the hypotenuse. we have that. sin(B)=cos(A) Remember that. A+B=90° -----> by complementary angles. so. A=90°-B. therefore. sin(B)=cos(A) sin(B)=cos(90°-B)Aug 22, 2023 · Cos 90 degrees is an important function used to find the solution of different trigonometric problems. However the first step is to be familiar with cos 90 degrees which includes how to represent cos 90 in terms of other trigonometric functions and trigonometric identities. Below are the following trigonometric identities which can represent ... Similar Problems from Web Search. sin(90−θ)= cos(θ) because: sin(α−β)= sin(α)cos(β)−cos(α)sin(β) How do you find the area of one petal of r = 6sin2θ ? 29π Explanation: Area in polar coordinates is given by: A= ∫ αβ 21r2 dθ The first step is to plot ... How do you find the value of sin20(θ) using the double angle identity?A formula for computing the trigonometric identities for the one-third angle exists, but it requires finding the zeroes of the cubic equation 4x 3 − 3x + d = 0, where is the value of the cosine function at the one-third angle and d is the known value of the cosine function at the full angle.Learn to find the sine, cosine, and tangent of 45-45-90 triangles and also 30-60-90 triangles. Until now, we have used the calculator to evaluate the sine, cosine, and tangent of an angle. However, it is possible to evaluate the trig functions for certain angles without using a calculator. An interesting trigonometry problem -- featuring roots of unity. YouTube Basic trigonometry | Basic trigonometry | Trigonometry | Khan Academy YouTube More Videos (sin(x))2 ⋅ ((cot(x))2 + 1) cos(π) tan(x) cos(3x + π) = 0.5 cot(x)sec(x) sin(x) .