49 A level Mathematics Edexcel Paper 1 2018 Q6 Part c)

This video explains how to find the value of a constant, k, in the equation of a tangent line to a circle. The process involves substituting the tangent line equation into the circle's equation, resulting in a quadratic equation. By using the discriminant of this quadratic, which must be zero for a tangent line, we can solve for k. The calculation involves expanding and simplifying expressions, identifying the coefficients a, b, and c, and then solving the resulting quadratic equation for k. This method allows us to find the specific value of k that defines the tangent line, distinguishing it from a previously identified tangent. Visit AxiomTutoring.com and subscribe to @AxiomTutoringCourses for more math tutorials.