df=-5*(-5)(cos(2x-1))^(-6)*(cos(2x-1))'dx=25(cos(2x-1))^(-6)*(-sin(2x-1))*(2x-1)'dx=-25(cos(2x-1))^(-6)*sin(2x-1)*2dx=-50(cos(2x-1))^(-6)*sin(2x-1)dx
df=-5*(-5)(cos(2x-1))^(-6)*(cos(2x-1))'dx=25(cos(2x-1))^(-6)*(-sin(2x-1))*(2x-1)'dx=-25(cos(2x-1))^(-6)*sin(2x-1)*2dx=-50(cos(2x-1))^(-6)*sin(2x-1)dx