Question

Cos 48 cos 12 - sin 48 sin12

Answer 1

cos A cos B - sin A sin B = cos ( A+B )

⇒cos 48 cos 12 - sin 48 sin 12

= cos (48+12)

= cos 60

= 1/2

Answer 2

$\cos 48 \cos 12 - \sin 48 \sin 12= \dfrac{1}{2}$

Step-by-step explanation:

We have,

$\cos 48 \cos 12 - \sin 48 \sin 12$

To find, the value of $\cos 48 \cos 12 - \sin 48 \sin 12$ = ?

∴ $\cos 48 \cos 12 - \sin 48 \sin 12$

=$\cos (48+12)$

[ ∵ $\cos (A+B)=\cos A \cos B - \sin A \sin B$]

$=\cos 60$

= $\dfrac{1}{2}$

[ ∵ $\cos 60=\dfrac{1}{2}$]

Hence, $\cos 48 \cos 12 - \sin 48 \sin 12= \dfrac{1}{2}$