设M=∫-π/2π/2sinx/(1+x2)cos4xdx,N=∫-π/2π/2(sin3x+cos4x)dx,P=∫-π/2π/2(x2sin3x-cos4x)dx,则有

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问题 设M=∫-π/2π/2sinx/(1+x2)cos4xdx,N=∫-π/2π/2(sin3x+cos4x)dx,P=∫-π/2π/2(x2sin3x-cos4x)dx,则有

选项 A、N<P<M
B、M<P<N
C、N<M<P
D、P<M<N

答案D

解析 M=∫[-π/2π/2sinxcos4/(1+x2)]dx=0,
N=∫[-π/2π/2(sin3x+cos4x)dx=∫[-π/2π/2cos4xdx>0,
P=∫[-π/2π/2(x2sin3x-cos4x)dx=-∫[-π/2π/2cos4xdx<0,P<M<N,选D.
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