Geometryhard · Past Paper

If the line y = mx + c is tangent to the circle x^2 + y^2 = r^2, then:

Ac^2 = r^2(1 + m^2)
Bc^2 = r^2(1 - m^2)
Cc = r*m
Dc = r/m

✓ Correct Answer: Ac^2 = r^2(1 + m^2)

This is the condition of tangency for a line and a circle centered at the origin.

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