Q. The tangent to the curve $y = 2x^{2} - x + 1$ at a point $P$ is parallel to $y = 3x + 4$, then the coordinates of $P$are

A) (2, 1)
B) (1, 2)
C) $( - 1,\ 2)$
D) $(2,\ - 1)$
Explanation

(b)
Given curve is $y = 2x^{2} - x + 1$
Let the coordinate of $P$ are $(h,\ k)$
On differentiating w.r.t. $x$, we get
$\frac{dy}{dx} = 4x - 1$
At the point $(h,\ k)$, the slope
$= \left( \frac{dy}{dx} \right)_{(h,\ k)} = 4h - 1$
Since, the tangent is parallel to the given line $y = 3x + 4$
$\Rightarrow \ \ 4h - 1 = 3\ \ \Rightarrow \ \ h = 1,\ k = 2$
$\therefore$ Coordinates of point $P$ are (1, 2)

Dr. Abubacker
Reviewed by Dr. Abubacker

Physics Educator & NEET/JEE Specialist

Ph.D. in Physics with 19+ years of teaching experience.