你的问题出在二重积分计算上面,
画出L所围区域,
可以看成Y型区域,
1≤y≤2,y²≤x≤4
应用格林公式,得到
原式=∫∫(-1/x²+1/y²)dxdy
=∫(1→2)dy∫(y²→4)(-1/x²+1/y²)dx
=∫(1→2) (1/x+x/y²)|(y²→4) dy
=∫(1→2) (1/4+4/y²-1/y²-1)dy
=∫(1→2) (3/y²-3/4)dy
=(-3/y-3y/4) |(1→2)
=(-3/2-3/2)-(-3-3/4)
=3/4
追问![](https://video.ask-data.xyz/img.php?b=https://iknow-pic.cdn.bcebos.com/622762d0f703918f70c85f2b563d269759eec432?x-bce-process=image%2Fresize%2Cm_lfit%2Cw_600%2Ch_800%2Climit_1%2Fquality%2Cq_85%2Fformat%2Cf_auto)
您讲的我明白了 但是要当成x型区域 这么列式子我算不出来