∫(x²-2xy)dx+(y²-2xy)dy
=∫[-1→1] (x²-2x*x²+(x^4-2x*x²)*2x)dx
=∫[-1→1] (x²-2x³+2x^5-4x^4)dx
由于积分区间对称,将奇函数部分删去
=∫[-1→1] (x²-4x^4)dx
=2∫[0→1] (x²-4x^4)dx
=2[(2/3)x³-(4/5)x^5] |[0→1]
=-4/15
∫(x²-2xy)dx+(y²-2xy)dy
=∫[-1→1] (x²-2x*x²+(x^4-2x*x²)*2x)dx
=∫[-1→1] (x²-2x³+2x^5-4x^4)dx
由于积分区间对称,将奇函数部分删去
=∫[-1→1] (x²-4x^4)dx
=2∫[0→1] (x²-4x^4)dx
=2[(2/3)x³-(4/5)x^5] |[0→1]
=-4/15