Question

Simplify the expression using sum or difference identities cos(12)cos(-3)-sin(12)sin(-3)​

Answer 1

Answer:

when you simplify the answer is -0.91113026

Step-by-step explanation:

Answer 2

Answer:

$\cos(12)\cos(-3)-\sin(12)\sin(-3)​=0.98$

Step-by-step explanation:

Given : Expression $\cos(12)\cos(-3)-\sin(12)\sin(-3)$

To find : Simplify the expression ?

Solution :

Expression $\cos(12)\cos(-3)-\sin(12)\sin(-3)$

We know the trigonometry identity,

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

Here, A=12 and B=-3

$\cos(12)\cos(-3)-\sin(12)\sin(-3)=\cos(12+(-3))$

$\cos(12)\cos(-3)-\sin(12)\sin(-3)=\cos(12-3)$

$\cos(12)\cos(-3)-\sin(12)\sin(-3)​=\cos(9)$

From calculator, $\cos 9=0.98$ in degrees.

Therefore, $\cos(12)\cos(-3)-\sin(12)\sin(-3)=0.98$