Question

write the following using only one trig function: cos20cos300+sin20sin300

Answer 1

\[\cos (a-b)=\cos a \cos b+\sin a \sin b\]

Answer 2

how we are gonna plug it in?

Answer 3

Maybe you could just match it up

Answer 4

how can we find cos20 in unit circle?

Answer 5

Can you see that a = 20 and b = 300?

Answer 6

Replace every a with 20 and every b with 300