This classmate, when you do the problem, you should read the conditions given by the problem clearly! P is a point on the midline of the isosceles triangle ABC, the three lines of the isosceles triangle are in one place, the midline is a vertical line, and the vector CP= vector CD+ vector DP, where D is the midpoint of BC, CD∑BC, DP⊥BC, the answer will not come out, and it takes 1 minute to make it. I hope it helps you. If you agree, please give me a compliment.