Question

cos 100°.cos 40° +sin 100°.sin 40°

​

Answer 1

Step-by-step explanation:

cos(100-40)=cos(60)

1/2

mark as brilliant....

Answer 2

Answer:

cos 100° .cos 40° + sin 100° .sin 40°

by using formula

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

=cos(100° - 40°)

=cos(60°)

=1/2