I'm doing a derivation in a variation of polar with 4-dimensions. I've gotten to the step below, I'm trying to solve for x in terms of the other 6 variables. I can't figure out where to go from this point on, I've tried multiple things but none helped. I was wondering if anybody is able to help with this?
$$ \cos\theta_{1}\cdot\sin\phi_{1}\cdot\sin\tau_{1}\cdot\cos\tau_{2}+\sin\theta_{1}\cdot\sin\phi_{1}\cdot\sin\tau_{1}\cdot\cos\phi_{2}\cdot\sin\tau_{2}-\cos\phi_{1}\cdot\sin\tau_{1}\cdot\sin\theta_{2}\cdot\sin\phi_{2}\cdot\sin\tau_{2}+\cos\tau_{1}\cdot\cos\theta_{2}\cdot\sin\phi_{2}\cdot\sin\tau_{2}=\cos x $$