Question
Find the integral of the function ${\frac{{\cos 2x - \cos 2\alpha }}{{\cos x - \cos \alpha }}}$
$= \int {\frac{{\left( {2{{\cos }^2}x - 1} \right) - \left( {2{{\cos }^2}\alpha - 1} \right)}}{{\left( {\cos x - \cos \alpha } \right)}}} dx$
$= \int {\frac{{\left( {2{{\cos }^2}x} \right) - \left( {2{{\cos }^2}\alpha} \right)}}{{\left( {\cos x - \cos \alpha } \right)}}} dx$
$ = \int {\frac{{2\left( {\cos^2 x - \cos^2 \alpha } \right)}}{{\left( {\cos x - \cos \alpha } \right)}}} dx$
$ = \int {\frac{{2\left( {\cos x + \cos \alpha } \right)\left( {\cos x - \cos \alpha } \right)}}{{\left( {\cos x - \cos \alpha } \right)}}} dx$
$ = \int 2({cos x + cos \alpha })\ dx$
$= 2\left( {\sin x + x\cos \alpha } \right) + c$.
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.