定积分，请给出画圈部分的详细步骤

---

此处印刷有误，f(1) 应为 ∫<1, 1> sintdt/t = 0
...... = （1/2）∫<1, 1> sintdt/t - (1/2)∫<0, 1> sinx^2dx^2
= 0+ (1/2)[cosx^2]<0, 1>
= (1/2)(cos1-1)

---

圈里第一个积分下限应该是1，f（1）=0

---

---