Question

Find the value of cos square 15 degree​

Answer 1

Answer:

cos square 15

then

cos (2×15)

cos 30

underroot 3/2

Answer 2

Answer:-

The correct answer is: (√3+1/2√2)

Explanation:-

cos(15°)=cos(45°-30°)

=cos45° cos 30° +sin45° sin 30°

=(1/√2 ) (√3/2) +(1/√2) (1/2)

=√3/2√2) +(1/2√2)

=√3+1/2√2

Here we have used formula cos(a-b)=cosa cosb+sina sinb

Now, cos^2(15°)=(√3+1/2√2)^2

Different formulas of trigonometry:-

sin(x + y) = sin(x)cos(y) + cos(x)sin(y)

sin(x + y) = sin(x)cos(y) + cos(x)sin(y)

 cos(x + y) = cos(x)cos(y) – sin(x)sin(y)

cos(x + y) = cos(x)cos(y) – sin(x)sin(y) 

sin θ = 1/cosec θ

cos θ = 1/sec θ

tan θ = 1/cot θ

sec θ = 1/cos θ

cot θ = 1/tan θ

cosec θ = 1/sin θ

For more references:-

https://brainly.in/question/4068827?utm_source=android&utm_medium=share&utm_campaign=question

https://brainly.in/question/225630?utm_source=android&utm_medium=share&utm_campaign=question

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