[tex]\begin{align*} \cos (2x) &= \cos^2(x)-\sin^2(x) \\ &=1-2\sin^2(x) \\ &= 2\cos^2(x)-1 \end{align*}[/tex]
gives
Hi there,
I had a little trouble getting your method to work for me. I was however able to achieve it using the tabbing environment. Once I get a bit better with LaTeX I will return to your suggested method, but for now I can carry on with the tabbing method.
Many thanks.