Question

Simplify:

sin50 x cos20 - sin40 x sin20

Answer 1

Hey, do you mean
sin(50)cos(20)-sin(40)sin(20?

Answer 2

Yes

Answer 3

Please use asterisks (*) for multiplication. We usually use "x" for a variable.

Answer 4

hint:
cos(x)=sin(90-x)

Answer 5

cos(90-50)*cos20 - cos(90-40).cos(90-20) = -cos20 (cos(90-50) - cos (90-40))

Answer 6

cos(90-50)*cos20-cos(90-40)*cos(90-20)
=cos(40)cos(20)-cos(50)cos(70)

Answer 7

=cos(40)cos(20)-sin(40)sin(20)

Answer 8

cos(alpha+beta)=cos(alpha)cos(beta)-sin(alpha)sin(beta)

Answer 9

Thanks!