Question

cos38cos-sin38sin52​

Answer 1

Answer:

cos 38.cos 52 - sin 38. sin 52

using formula,

cos(A+B) = cosA cosB - sinA sinB

A/c question

A = 38

B = 52

then ,

cos(A+B ) = cos (38°+ 52°)

= cos (90°)

= 0 answer

I hope it helps you

Answer 2

Answer:

we know that

cos (a+b)=cos a cos b -sin a sin b

so

=cos (38+52)

= cos 90°

= 0