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问题: 几道数学题目(急)

还是求导..
1)(arcctg1/x)^2
2)y=a根号x * x^2
3)y=x * arcsinx + 根号1-x^2

解答:

1)y=[arcctg(1/x)]^2
y'=[-1/(1+x^2)](1/x)'
=[-1/(1+x^2)](-1/x^2)
=1/(1+x^2)x^2

2)y=a√x * x^2=ax^(5/2)
y'=a(5/2)x^(3/2)=(5a/2)x^(3/2)

3)y=x * arcsinx + √(1-x^2)
y'=arcsinx+[x/√(1-x^2)]+(1/2)(-2x)/√(1-x^2)
=arcsinx