JAMB - Mathematics (1991 - No. 28)
At what value of x is the function y = x2 - 2x - 3 minimum?
1
-1
-4
4
คำอธิบาย
For y = ax2 - bx + c for minimum y
\(\frac{dy}{dx}\) = 2x - 2
= \(\frac{dy}{dx}\) = 0
∴ 2x - 2 = 0
x = 1
\(\frac{dy}{dx}\) = 2x - 2
= \(\frac{dy}{dx}\) = 0
∴ 2x - 2 = 0
x = 1