Question: If cosA = 12/13, find sinA and tanA. Solution: Given, cosA = 12/13 We know, sinA =  So, sinA = 5/13 Now, tanA =  So, tanA = 5/12 So, the required values of sinA and tanA when cosA = 12/13 are 5/13 and 5/12, respectively. Explanation: This is a general question from…

Prove that: cot π/20 . Cot 3π/20 . Cot 5π/20 . Cot 7π/20 . Cot9π/20 = 1 We use the value: $π^c$ = 180° Answer : Taking LHS = cot $\frac{π^c}{20}$ .cot $\frac{3π^c}{20}$ .cot$\frac{5π^c}{20}$ .cot $\frac{7π^c}{20}$ .cot $\frac{9π^c}{20}$ …

Find the value of: Cos20° + cos40° + cos140° + cos160° Answer: I won't explain the answer but rather show you the values of them. Once you put the value of sin and cos as indicated in the question and perform the basic Mathematics, you will get your answer. Also, you need to understand these formulas (a pa…

Prove that: Cos²7π/8 + cos²5π/8 +cos²3π/8 + cos²π/8 = 2 Answer: I won't explain the answer but rather show you the values of them. Once you put the value of sin and cos as indicated in the question and perform the basic Mathematics, you will get your answer. Also, you need to understand these formulas (a p…

Find the value of: [ tan(180-Θ). cot(90-Θ). cos(360-Θ) ] [ sin(-Θ). tan(90+Θ). tan(180-Θ)] Answer: I won't explain the answer but rather show you the values of them. Once you put the value of sin and cos as indicated in the question and perform the basic Mathematics, you will get your answer. Also, you nee…

Prove that:  Cosπ/8 + cos3π/8 + cos5π/8 + cos7π/8 = 0 Answer: I won't explain the answer but rather show you the values of them. Once you put the value of sin and cos as indicated in the question and perform the basic Mathematics, you will get your answer. Advertisement Also, you need to understand thes…

If sinA = 12/13 , find cosA and tanA. This is question from the Values of Trigonometric Ratios chapter of Unit Trigonometry. You can find the solution in the picture and the brief explanation is given below the image. Here is the solution. Answer: This is one of the easiest question in Trigonometry! When we have been g…

Find the value of: cosec(-1485°) Answer: Here, to find the value of cosec at -1485° angle we need to make sure that we know the CAST FORMULA. We might need to use formula of cosec at 90-x or 90+x or 180+x or 360-x and so on. But how do we know which one is the correct? So, let me give you a quick tri…

Unit-6.2   |  Trigonometric Ratios of Standard Angles and Any Angles   |  Class-09 What are standard angles? Trigonometric values of angles such as 0°, 30°, 45°, 60°, and 90°, etc. that can be derived geometrically are known as standard angles. Values of Trigonometric Ratios of Standard Angles: Understanding the values of Trigonome…