y^2 = 4x
.: dy/dx = 2/y
The derivative evaluated at (1,2) gives the tangential gradient.
The negative inverse of the gradient gives the gradient of the normal, and hence the equation of the normal line through (1,2).
The equation of the normal line, and the given radius (4) allows you to find the centres of the circles.
The centre points and the radius allow you to write the equations for the circles.
Two circles of radius 4 are tangent to the graph of y^2=4x at the point (1,2). Find equations of these two circles.
I found the derivative of y^2=4x, but i don't know what to do next!
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