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y=ln[x+(x^2+a^2)^(1/2)]的导数怎么求.

题目详情
y=ln[x+(x^2+a^2)^(1/2)]的导数怎么求.
▼优质解答
答案和解析
y'=1/[x+√(x²+a²)]*[x+√(x²+a²)]
=1/[x+√(x²+a²)]*[1+1/2√(x²+a²)*(x²+a²)']
=1/[x+√(x²+a²)]*[1+2x/2[x+√(x²+a²)]
=1/[x+√(x²+a²)]*[x+√(x²+a²)]/√(x²+a²)
=1/√(x²+a²)