在直角坐标系xoy中,已知曲线C1:x=t+2,y=1-2t,(t为参数)
问题描述：
在直角坐标系xoy中,已知曲线C1:x=t+2,y=1-2t,(t为参数)
与曲线C2:x=3cosθ,y=3sinθ(θ为参数）相交于A,B两个点,则AB线段的长?要计算过程,
答
x = t + 2,t = x - 2y = 1 - 2t = 1 - 2(x - 2) = 5 - 2x,2x + y - 5= 0 (1) 直线x=3cosθ,y=3sinθx² + y² = (3cosθ)² + (3sinθ)² = 9(cos²θ + sin²θ) = 9 (2) 圆心为原点半径为...AB/2 = √(r² - d²) = √(9 - 5) = 2????称AB的中点为C, OC = d = √5OAC为直角三角形，斜边OA = r = 3AC = √(OA² - OC²) = √(r² - d²) ......AB = 2AC