Question

Find the equation of a circle with center (-4,2) and tangent to line 2x-y+2=0.

Answer 1

you have the equation of the tangent line so first find the slope of it. we'll use that.

Answer 2

the equation of a circle with radius r and centered at (a,b)
is
(X-a)^2+(y-b)^2 = r^2

Answer 3

your job is to find the radius at which that tangent line belongs to this circle

Answer 4

2 is the slope

Answer 5

so what is the slope of a line perpendicular to it?

Answer 6

how to find the radius in the equation?

Answer 7

we're getting there...

Answer 8

- 1/2 is the slope perpendicular to it