Question

$x^2=4y$ : Find the equation of tangent passing through (-1,2)

Answer 1

$x^2=4y$

Slope of tangent at any point is given by $\frac{dy}{dx}$

Differentiating w.r.t x

$2x=4\frac{dy}{dx}\frac{dy}{dx}=\frac{x}{2}$

At point $(-1,2)$

${\frac{dy}{dx}|}_{(-1,2)}=\frac{-1}{2}$

Equation of tangent passing through $(-1,2)$

$y-2=\frac{-1}{2}(x+1)2y-4=-x-1x+2y-3=0$