设函数<img src="https://static.zxtiku.com/wangke/imgs/topic/c43410d6488ea3f3fd88e4c7383823e8.png"/>有二阶导数且<img src="https://static.zxtiku.com/wangke/imgs/topic/b8ffc6197b63663f517cac99b296eadc.png"/>，过曲线<img src="https://static.zxtiku.com/wangke/imgs/topic/7622a53140243ac41f7a479fa870df60.png"/>上任意一点<img src="https://static.zxtiku.com/wangke/imgs/topic/f88dc78382aca080c92ba9f663d1eb1b.png"/>作该曲线的切线<img src="https://static.zxtiku.com/wangke/imgs/topic/ea0e1bba5eb79d0dd8b70de87741bbc5.png"/>及x轴的垂线，上述两条直线与x轴所围成的三角形的面积记为<img src="https://static.zxtiku.com/wangke/imgs/topic/1aeb465237289b621ec0e443b4701e61.png"/>，区间<img src="https://static.zxtiku.com/wangke/imgs/topic/cd853da3fc61681bcdefe8658358b5e5.png"/>上以<img src="https://static.zxtiku.com/wangke/imgs/topic/e915ab4029f9b6397ea50cffdf57a16b.png"/>为曲边的曲边梯形的面积记为<img src="https://static.zxtiku.com/wangke/imgs/topic/bebb03899d0dbff143e24763b81d1560.png"/>，且<img src="https://static.zxtiku.com/wangke/imgs/topic/db75c612bfb3c53648d431f11c401dba.png"/>恒为1，则曲线<img src="https://static.zxtiku.com/wangke/imgs/topic/09725c24caa049fc3a4130590c44102c.png"/>的方程为（）.