Question

the value of cos^2 15+cos^2 75

Answer 1

The value of cos² 15° + cos² 75° = 1

Correct question : Find the value of cos² 15° + cos² 75°

Given :

The expression cos² 15° + cos² 75°

To find :

The value of the expression

Formula :

• cos (90° - θ) = sin θ

• sin² θ + cos² θ = 1

Solution :

Step 1 of 2 :

Write down the given expression

Here the given expression is

cos² 15° + cos² 75°

Step 2 of 2 :

Find the value of the expression

cos² 15° + cos² 75°

= cos² (90° - 75°) + cos² 75°

= sin² 75° + cos² 75° [ ∵ cos (90° - θ) = sin θ ]

= 1 [ ∵ sin² θ + cos² θ = 1 ]

∴ cos² 15° + cos² 75° = 1

━━━━━━━━━━━━━━━━

Learn more from Brainly :-

$1.$ If cosθ+secθ=√2,find the value of cos²θ+sec²θ

https://brainly.in/question/25478419

2. Value of 3 + cot 80 cot 20/cot80+cot20 is equal to

https://brainly.in/question/17024513

#SPJ3