Question

A chord of the parabola y = x² - 2 + 5 = joins the point with the abscissas x₁ x 1 , x₂ =  3 Then the equation of the tangent to the parabola parallel to the chord is :

(A)   2x  - y + 5/4  = 0

(B)   2x – y + 2 = 0

(C)   2x – y + 1 = 0

(D)   2x + y + 1 = 0

Answer 1

Correct option  (C ) 2x - y + 1 = 0

Explanation:

Equation of chord joining the points Equation of chord joining the points P(1,4) & (3,8) on the parabola is 2x - y +  2 = 0 

Tangent parallel to this chord will have the slope i.e dy/dx = 2

∴  Equation of tangent at (α ,β) on the curve with slope 2 is 2x - y + 1 = 0