Question

cos ( 45° + x ) + cos ( 45° - x ) = ?

Answer 1

Step-by-step explanation:

use the formula Cos(A+B) and Cos (A-B)

Answer 2

$\cos ( 45^\circ + x ) +\cos ( 45^\circ - x )=\sqrt2\cos x$

Step-by-step explanation:

To find : $\cos ( 45^\circ + x ) +\cos ( 45^\circ - x ) = ?$

Solution :

Using trigonometric property,

$\cos(A+B)+\cos(A-B)=2\cos A\cos B$

Here, A=45 and B=x

Substitute in the formula,

$\cos ( 45^\circ + x ) +\cos ( 45^\circ - x )=2\cos 45^\circ\cos x$

We know, $\cos 45^\circ=\frac{1}{\sqrt2}$

$\cos ( 45^\circ + x ) +\cos ( 45^\circ - x )=2(\frac{1}{\sqrt2})\cos x$

$\cos ( 45^\circ + x ) +\cos ( 45^\circ - x )=\sqrt2\cos x$

#Learn more

5sin 30°+3tan 45°, Find the values of it

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