f′(x)=(x2)′sinx+x2(sinx)′=2xsinx+x2cosx,
∴f'(π2)=π
故答案为:π.
A normal distribution can be completely described by its:()
A. mean and variance.
B. skewness and kurtosis.
C. mean and mode.
溶血性黄疸()
A.黄疸伴贫血
B.皮肤瘙痒、陶土便
C.黄疸、转氨酶明显升高
D.血总胆红素升高
E.尿色呈豆油黄色