circle p is tangent to the x axis and the y axis. if the coordinates ofthe center are (r, r) find the equation of the line containing the points of tangencyA) x + y= rB) x-y=rC) x+y=1
Accepted Solution
A:
we know that Circle p is tangent to the x axis and the y axis so the point in the x axis is (0,r) the point in the y axis is (r,0)
the equation of the line that containing the points of tangency is point A(0,r) point B(r,0) m=(y2-y1)/(x2-x1)------> m=(0-r)/(r-0)------> m=-r/r------> m=-1
with m=-1 and point A(0,r) y-y1=m(x-x1)-------> y-r=-1*(x-0)-----> y=-x+r--------> y+x=r