A curve has equation \(y = f(x)\). It is given that \(f'(x) = 3x^2 + 2x - 5\).
Given that the curve passes through \((1, 3)\), find \(f(x)\).
Solution
To find \(f(x)\), we need to integrate \(f'(x) = 3x^2 + 2x - 5\).
The integral of \(3x^2\) is \(x^3\), the integral of \(2x\) is \(x^2\), and the integral of \(-5\) is \(-5x\). Therefore,
\(f(x) = x^3 + x^2 - 5x + c\), where \(c\) is the constant of integration.
We use the point \((1, 3)\) to find \(c\). Substituting \(x = 1\) and \(f(x) = 3\) into the equation:
\(3 = 1^3 + 1^2 - 5(1) + c\)
\(3 = 1 + 1 - 5 + c\)
\(3 = -3 + c\)
\(c = 6\)
Thus, \(f(x) = x^3 + x^2 - 5x + 6\).
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