作函数图像：

y=xlogx
y=x^2

作函数图像：

y=x^3+20
y=x^3+x

作函数图像：

y=35.42(x-9)(x-0)/162-32.34(x-18)(x-0)/81+41.53(x-9)(x-18)/162

作函数图像：

y=2sin(2x＋π/6)＋1

作函数图像：

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