có: \(y= cot(\sqrt{2x^2 + 1})\)
\(\Rightarrow y'=[cot(\sqrt{2x^2+1})]'=-\frac{(\sqrt{2x^2+1})'}{sin^2(\sqrt{2x^2+1})}=-\frac{({2x^2+1})'}{2\sqrt{2x^2+1}.sin^2(\sqrt{2x^2+1})}\)
\(=-\frac{4x}{2\sqrt{2x^2+1}.sin^2(\sqrt{2x^2+1})}=-\frac{2x}{\sqrt{2x^2+1}.sin^2(\sqrt{2x^2+1})}\)
Chúc bạn học tốt!