JAMB - Mathematics (2001 - No. 24)
If the gradient of the curve y = 2kx2 + x + 1 at x = 1 is 9, find k.
4
3
2
1
Giải thích
y = 2kx2 + x + 1
Gradient function dy/dx = 4kx + 1
at dy/dx = 9, => 9 = 4kx + 1
=> 8 = 4kx, and k = 8/4x.
At x = 1, k = 8/4 = 2
Gradient function dy/dx = 4kx + 1
at dy/dx = 9, => 9 = 4kx + 1
=> 8 = 4kx, and k = 8/4x.
At x = 1, k = 8/4 = 2