斜率为1的直线经过抛物线y^2=4x的焦点,且与抛物线相交于A,B两点,则绝对值AB等于____
问题描述：
斜率为1的直线经过抛物线y^2=4x的焦点,且与抛物线相交于A,B两点,则绝对值AB等于____
答
y^2=4x = 2*2x = 2px p = 2焦点F(p/2,0),即(1,0)设直线方程为 y = x + b过F(1,0),0 = 1 + b,b = -1y = x -1(x-1)^2 = 4xx^2 -6x + 1 = 0x1 = 3 - 2√2,x2 = 3+2√2y1 = 2 - 2√2,y2 = 2+2√2|AB| = √[(x2 -x1)^2 + ...