(17) int dfrac (2cdot {3)^x-5cdot (2)^x}({3)^x}dx-|||-(18) (int )_(e)^exe(sex-tan x)dx;-|||-(19) (int )_(cos )^2dfrac (x)(2)dx;-|||-(20) int dfrac (dx)(1+cos 2x);-|||-(21) int dfrac (cos 2x)(cos x-sin x)dx;-|||-(22) int dfrac (cos 2x)({cos )^2x(sin )^2x}dx;-|||-(25) cot ^2xdx;-|||-(24) int cos theta (tan theta +sec theta )dtheta ;-|||-(25) int dfrac ({x)^2}({x)^2+1}dx;-|||-(26) int dfrac (3{x)^4+2(x)^2}({x)^2+1}dx.