Oh so I would use the formula for PE which is mgh, and since its at the top of its swing the PE is the TE so TE = mgh, then isolate for h, convert that to L(1-cos(θ)) and have the new equation L(1-cos(θ))= TE/mg, then further isolate the cos(θ) to cos(θ) = -1 + TE/MGL. then i get the angular...