So it's been a while since I've needed to use trig identities to solve problems, so when I came across this one I found myself stuck pretty quickly.
20 * cos^2(theta) = 35 * sin(theta) * cos(theta) + 3.0816
what I tried so far was to change the sin and cos on the right side to 17.5 sin(2 theta)
then I tried to change the cos^2 to 1 - sin^2
and from there I thought I could maybe turn it into a quadratic, but with the second sin having 2 theta on the inside, wasn't really sure how to continue on this one.