判断函数的奇偶性:y=xsin(5x-5/2丌)依格式如下:y=-3cos4xf(-x)=-3cos4x(-x)=-3cos4x=f(x)所以y=-3cos4x为偶函数

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判断函数的奇偶性:y=xsin(5x-5/2丌)依格式如下:y=-3cos4xf(-x)=-3cos4x(-x)=-3cos4x=f(x)所以y=-3cos4x为偶函数
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判断函数的奇偶性:y=xsin(5x-5/2丌)依格式如下:y=-3cos4xf(-x)=-3cos4x(-x)=-3cos4x=f(x)所以y=-3cos4x为偶函数
判断函数的奇偶性:y=xsin(5x-5/2丌)
依格式如下:y=-3cos4x
f(-x)=-3cos4x(-x)
=-3cos4x
=f(x)
所以y=-3cos4x为偶函数

判断函数的奇偶性:y=xsin(5x-5/2丌)依格式如下:y=-3cos4xf(-x)=-3cos4x(-x)=-3cos4x=f(x)所以y=-3cos4x为偶函数
f(-x)=-xsin(-5x-5/2丌)
= xsin(5x-3/2 丌)
=xsin(5x+1/2 丌)
=xcos5x
f(x)=xsin(5x-1/2丌)=-xcos5x
所以f(x)=-f(-x),所以函数是奇函数!

由公式sin(x-y)=sinxcosy-cosxsiny
sin(-x)=-sinx
得到sin(5x-5/2pi)=sin5xcos5/2pi-cos5xsin5/2pi
所以f(x)=xsin(5x-5/2pi)=xsin5xcos5/2pi-xcos5xsin5/2pi*******(1)
f(-x)=-xsin(-5x-5/2pi)=-xsin(-5x)c...

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由公式sin(x-y)=sinxcosy-cosxsiny
sin(-x)=-sinx
得到sin(5x-5/2pi)=sin5xcos5/2pi-cos5xsin5/2pi
所以f(x)=xsin(5x-5/2pi)=xsin5xcos5/2pi-xcos5xsin5/2pi*******(1)
f(-x)=-xsin(-5x-5/2pi)=-xsin(-5x)cos5/2pi+xcos(-5x)sin5/2pi
=xsin5xcos5/2pi+cos5xsin5/2pi*********(2)
比较(1)和(2),所以原函数非奇非偶

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