Question

write the given expression as the sine of an angle
sin40cos20+cos40sin20

Answer 1

It's $sin(40+20)=sin60=\frac{\sqrt3}2$

Answer 2

Yo sup??

The given expression is in the form

sinAcosB+cosAsinB

we know that

sin(A+B)=sinAcosB+cosAsinB

therefore

sin40cos20+cos40sin20=sin(40+20)

=sin60

=√3/2

Hope this helps.