Question

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

• A. (2, 1)
• B. (1, 2)
• C. (– 1, 2)`
• D. (2, – 1)

Answer 1

Answer: (B)

(1, 2)

Answer 2

Given $y = 2x^{2} - x + 1$

Let the co-ordinate of P is (h, k) then $\left( \frac{dy}{dx} \right)_{(h,k)} = 4h - 1$

Clearly $4h - 1 = 3$

$h = 1$ ⇒ $k = 2$. P is (1, 2).