How do you solve #cos^3x-2sinx-0.7=0#?
1 Answer
We cannot exactly solve it, but there are approximate solutions at
Explanation:
We cannot exactly solve the equation with the given values.
What we want to do, generally, is combine trigonometric terms using identities. Here, there aren't any useful identities, even if we start breaking things up.
If we plot the function,
graph{-0.7-2sin(x) + cos(x)^3 [-10, 10, -5, 5]}
we see that it is periodic with period
I'll go into a little nitty gritty here, using complex exponentials:
We can let
So we have a 6th order complex polynomial in terms of