题目
设 Phi(x)= int_(sin x)^0 (dt)/(1 + t^2)，则 Phi'(x)= ( )。A. (1)/(1 + sin^2 x)B. (cos x)/(1 + sin^2 x)C. -(cos x)/(1 + sin^2 x)D. -(1)/(1 + sin^2 x)
设 $\Phi(x)= \int_{\sin x}^{0} \frac{dt}{1 + t^2}$，则 $\Phi'(x)= (\quad)$。
A. $\frac{1}{1 + \sin^2 x}$
B. $\frac{\cos x}{1 + \sin^2 x}$
C. $-\frac{\cos x}{1 + \sin^2 x}$
D. $-\frac{1}{1 + \sin^2 x}$
题目解答
答案
C. $-\frac{\cos x}{1 + \sin^2 x}$