数学题What is they-intercept of the line tangent to the circle
数学题What is they-intercept of the line tangent to the circle x²+y
这是网友给的答案和解题的图片.求问切线AB的斜率怎么算?数字是怎么出来的?
过圆X²+ Y²= 1的切点P(3/5,4 / 5)的切线AB在Y轴上的截距为OB,求OB,
法线OP的斜率k=(4/5)/(3/5)=4/3,切线AB的斜率k1=-1/(4/3)=-3/4,
AB的切线方程,按点斜式有:y-4/5=(-3/4)(x-3/5)=(-3/4)x+9/20
y=(-3/4)x+5/4,x=0时,y=5/4,
切线AB在Y轴上的截距为5/4.
![](https://img.yulucn.com/upload/e/78/e78b88bf15145af7900e1fe6a21d64c4_thumb.jpg)
完整题目What is they-intercept of the line tangent to the circle x²+y²=1 at the point (3/5,4/5)?