1 answer

(click or scroll down)

## Sin^2(x) + cos^2(x) = 1

Answer is this. So easy way.

(cosAcosB-sinAsinb)^2 + (sinAcosB+cosAsinB)^2 = 1

Composite argument properties:

cos(A + B) = cosAcosB - sinAsinB

sin(A + B) = sinAcosB + cosAsinB

Substituting:

[cos(A + B)]^2 + [sin(A + B)]^2 = 1

Can you take it from here?

Rusif
answered

8 years ago

8 years ago

Answer is this. So easy way.