题目1单选题
由定积分的几何意义,<img src="https://tihai-oss-cloud.itihey.com/img/2770be51ed64f47e3597677e29230aee.gif">=A. <img src="https://tihai-oss-cloud.itihey.com/img/90e8a1ae0c61bd678cd430ff25ae1c1c.gif">B. 1C. <img src="https://tihai-oss-cloud.itihey.com/img/5009deaf9ed695e8ce8d3ac8b20f02f8.gif">D. 0