The line \(y = mx - 3\) is a tangent to the curve \(y =
FURTHER MATHEMATICS
WAEC 2009
The line \(y = mx - 3\) is a tangent to the curve \(y = 1 - 3x + 2x^{3}\) at (1, 0). Find the value of the constant m.
- A. -4
- B. -1
- C. 3
- D. 4
Correct Answer: C. 3
Explanation
\(y = 1 - 3x + 2x^{3}\)
\(\frac{\mathrm d y}{\mathrm d x} = -3 + 6x^{2}\)
At (1, 0), \(\frac{\mathrm d y}{\mathrm d x} = -3 + 6(1^{2}) = -3 + 6 = 3\)
\(y = mx - 3 \implies \frac{\mathrm d y}{\mathrm d x} = m = 3\) (Tangent with equal gradient)
Post an Explanation Or Report an Error
If you see any wrong question or answer, please leave a comment below and we'll take a look. If you doubt why the selected answer is correct or need additional more details? Please drop a comment or Contact us directly. Your email address will not be published. Required fields are marked *