Question

who ducking made trigonometry

Answer 1

Hello Dear!!!

Here's your answer...

Cos15

15 can be written as 45-30

Cos(45-30)

It is in the form of Cos(A-B)=CosA.CosB+SinA.SinB

Here,

A is 45

B is 30

Cos45.Cos30 + Sin45.Sin30

1/√2 * √3/2 + 1/√2 * 1/2

√3/ 2√2 + 1/ 2√2

√3 + 1 / 2√2

The value of Cos15 is √3+1 / 2√2

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HOPE THIS HELPS YOU....