Find the derivative of (4995)/(1+.12cosθ), when θ = 120°
My attempt:
d/dx [4995/(1+.12cosθ) = (4995)(-1)(1+.12cosθ)-2(.12)(-sinθ)
Letting θ = 120°...
= (4995)(-1)(1+.12(-1/2))-2(.12)(-\sqrt{3}/2)
My calculator says that is about 587.478
But it's supposed to be about 10.253...