The gradient of the curve y = mx\(^2\) + 3x – 1 at the point (-1, 1) is 9. Find the value of m
-
- 3
- 3
- \(\frac{-5}{4}\)
- \(\frac{5}{4}\)
The correct answer is: A
Explanation
y = mx\(^2\) + 3x - 1 at the point (-1, 1)
\(\frac{dy}{dx}\) = 9
\(\frac{dy}{dx}\) = 2mx + 3 = 9, but x = -1
2m(-1) + 3 = 9
-2m = 9 - 3 = 6
m = \(\frac{6}{-2}\) = - 3