SOLUTION: Write an equation for the line tangent to the circle x2 + y2 = 17, at the point (4, 1).

Algebra ->  Quadratic-relations-and-conic-sections -> SOLUTION: Write an equation for the line tangent to the circle x2 + y2 = 17, at the point (4, 1).      Log On


   

Question 946847: Write an equation for the line tangent to the circle x2 + y2 = 17, at the point (4, 1).
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
The slope of the tangent line is equal to the derivative at the point.
2xdx%2B2ydy=0
2ydy=-2xdx
m=dy%2Fdx=-x%2Fy
So at (4,1), the slope is equal to,
m=-4%2F1=-4
Using the point-slope form of a line,
y-1=-%284%29%28x-4%29
y-1=-4x%2B16
highlight%28y=-4x%2B17%29