Question

The equation of tangent to the parabola $y^2=4x$ at point (1, 2) is

• A. $x-y+1=0$
• B. $x+y+1=0$
• C. $x+y-1=0$
• D. $x-y-1=0$

Answer 1

Answer: (A)

Equation of tangent at (1, 2) is
$2y=2(x+1)$ $[\because y{y}_1=2(x+x_1)]$
$\Rightarrow$ $y=x+1$ $\Rightarrow$ $x-y+1=0$