Cos3x*tg5x найти производную

[latex]y'(x)=cos'(3x)*tg(5x)+cos(3x)*tg'(5x)=-3sin(3x)*tg(5x)+ \frac{5cos(3x)}{cos^{2}(5x)}=-\frac{3sin(3x)*sin(5x)}{cos(5x)}+\frac{5cos(3x)}{cos^{2}(5x)}=\frac{-3sin(3x)*sin(5x)*cos(5x)+5cos(3x)}{cos^{2}(5x)}=[/latex][latex]=\frac{-1.5sin(3x)*sin(10x)+5cos(3x)}{cos^{2}(5x)}[/latex]