Question

If sin a + sin 2 a = 1 , then what will be cos^2 a + cos^4 a is?

Answer 1

Answer:-

Given:-

$sin^2A+cos^2A=1$

To Find:-

Value of cos^2A + cos^4A.

Solution:-

⇒ $sin^2\theta+cos^2\theta=1$

then,

⇒ $sinA=1-sin^2A= cos^2A$

On squaring both sides, we get

⇒ $sin^2A=cos^4A$

⇒ $1-cos^2A=cos^4A$

⇒ $cos^2A+cos^4A=1$

Hence, the value of cos²A + cos⁴A is 1.

Explanation:-

Trigonometric identities are equalities which uses the trigonometric functions to make variables which is  true for every single value for occurring variables.