Q55 / 90 · JEE Main 2016 (10 Apr Online) · Mathematics

Let C be a curve given by yx=1+ 4x-3,x>34. If P is a point on C, such that the tangent at P has slope 23, then a point through which the normal at P passes, is :

  • Correct answer
    A
    1, 7
  • B
    3, -4
  • C
    4, -3
  • D
    2, 3

Solution

Given, 

yx=1+ 4x-3

So, dydx=124x-3 ×4=23

⇒ 4x-3=9

⇒ x=3

So, y=4

Equation of normal at  P3, 4 is y-4=-32x-3

i.e., 2y-8=-3x+9

⇒ 3x+2y-17=0

Hence only option A is satisfying the equation.

Hence, the correct answer is option: 'A'.

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