The question is: Using Eulers formula for e^±(adsbygoogle = window.adsbygoogle || []).push({}); iθ , obtain the trigometric identities for cos(θ1, θ2) and sin(θ1, θ2)

I think I have completed the real and imaginary solutions for the base e^+iθ using the real part cos(θ1+θ2)and imaginaryisin(θ1+θ2)

Gaining

cos(θ1 + θ2) = cosθ1 cosθ2 - sinθ1 sinθ2

sin(θ1 + θ2) = sinθ1 cosθ2 + cosθ1 sinθ2

My problem is how to proceed from here for the base e^-iθ

should my real and imaginary parts be in the form

cos(θ1-θ2) +isin(θ1-θ2)

or

cos(θ1+θ2) -isin(θ1+θ2)

Thanks in advance for any help

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Eulers formula problem

**Physics Forums | Science Articles, Homework Help, Discussion**