Question

if cos x equal to Cos 60 degree cos 30 degree + sin 60 degree sin 30 degree then find x

Answer 1

cosx=cos60.cos30+sin30.sin 60
cosx=1/2.root3/2+1/2(root3/2)
cosx=2(root3/4)
cosx=root3/4
cosx=cos30
x=30

Answer 2

The value of x is 30°.

Step-by-step explanation:

Given : $\cos x=\cos 60^\circ\cos 30^\circ+\sin 60^\circ\sin 30^\circ$

To find : The value of x ?

Solution :

Equation $\cos x=\cos 60^\circ\cos 30^\circ+\sin 60^\circ\sin 30^\circ$

Using trigonometric values,

$\cos 60^\circ=\frac{1}{2}$

$\cos 30^\circ=\frac{\sqrt3}{2}$

$\sin 60^\circ=\frac{\sqrt3}{2}$

$\sin 30^\circ=\frac{1}{2}$

Substitute the values in the equation,

$\cos x=(\frac{1}{2})(\frac{\sqrt3}{2})+(\frac{\sqrt3}{2})(\frac{1}{2})$

$\cos x=\frac{\sqrt3}{4}+\frac{\sqrt3}{4}$

$\cos x=\frac{2\sqrt3}{4}$

$\cos x=\frac{\sqrt3}{2}$

$\cos x=\cos 30^\circ$

On comparing x is 30.

Therefore, the value of x is 30°.

#Learn more

If cos is equal to 2 x is equal to Cos 60 degree into cos 30 degree + sin 60 degree into sin 30 degree find sin 2x

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