双曲线4x^2-9y^2=36被点(2,1)平分的弦所在直线方程_数学解答

双曲线4x^2-9y^2=36被点(2,1)平分的弦所在直线方程

人气：231 ℃　时间：2020-02-03 19:24:42

解答

y-1=k(x-2)y=kx+(1-2k)代入(4-9k²)x²-18k(1-2k)x-9(1-2k)²-36=0x1+x2=18k(1-2k)/(4-9k²)则重点横坐标=(x1+x2)/2=9k(1-2k)/(4-9k²)=29k-18k²=8-18k²k=8/9所以是8x-9y-7=0...