Question

вычислите производную f(x)=tgx(cosx+2)​

Answer 1

$f(x)=tgx(Cosx+2)\\\\f'(x)=(tgx)'*(Cosx+2)+tgx*(Cosx+2)'=\frac{1}{Cos^{2}x }*(Cosx+2)+tgx*(-Sinx)=\\\\=\frac{Cosx+2}{Cos^{2}x}-\frac{Sinx}{Cosx}*Sinx=\frac{Cosx+2}{Cos^{2}x}-\frac{Sin^{2}x }{Cosx}=\frac{Cosx+2-Sin^{2}x Cosx }{Cos^{2}x}=\\\\=\frac{Cosx(1-Sin^{2}x)+2 }{Cos^{2}x }=\frac{Cos^{3}x+2 }{Cos^{2}x}$

Второй способ :

$f(x)=tgx(Cosx+2)=\frac{Sinx}{Cosx}*Cosx+2tgx=Sinx+2tgx\\\\f'(x)=(Sinx)'+2(tgx)'=Cosx+\frac{2}{Cos^{2}x }=\frac{Cos^{3}x+2 }{Cos^{2}x}$