1/ \(y'=\left(1-3x\right)'\sqrt{x-3}+\left(1-3x\right)\left(\sqrt{x-3}\right)'=-3\sqrt{x-3}+\dfrac{1}{2\sqrt{x-3}}\left(1-3x\right)\)
2/ \(y'=\dfrac{1}{\sqrt{2x+1}}-\dfrac{1}{\left(x+1\right)^2}\)
3/ \(y'=\dfrac{1}{2}.\sqrt{\dfrac{1+x}{1-x}}.\left(\dfrac{1-x}{1+x}\right)'=\dfrac{1}{2}\sqrt{\dfrac{1+x}{1-x}}.\dfrac{-2}{\left(1+x\right)^2}=-\sqrt{\dfrac{1+x}{1-x}}.\dfrac{1}{\left(1+x\right)^2}\)
4/ \(y'=\left(\cos5x\right)'.\cos7x+\cos5x.\left(\cos7x\right)'=-5\sin5x.\cos7x-7\cos5x\sin7x\)
5/ \(y'=\left(\cos x\right)'\sin^2x+\cos x\left(\sin^2x\right)'=-\sin^3x+2\sin x.\cos^2x\)
6/ \(y'=\left(\tan^42x\right)'=4.\tan^32x.\dfrac{2}{\cos^22x}\)
7/ \(y'=\dfrac{2\sin x+2\cos x-2x.\cos x+2x\sin x}{\left(\sin x+\cos x\right)^2}\)
Ờm, bạn tự rút gọn nhé :) Mình đang hơi lười :b