Definite Integral 0B31Ca
1. The problem is to understand the definite integral \(\int_a^b f(x)\,dx\), which represents the area under the curve of the function \(f(x)\) from \(x=a\) to \(x=b\).
2. The formula for the definite integral is:
$$\int_a^b f(x)\,dx = F(b) - F(a)$$
where \(F(x)\) is any antiderivative of \(f(x)\), meaning \(F'(x) = f(x)\).
3. Important rules:
- The limits \(a\) and \(b\) are the bounds of integration.
- The integral calculates the net area, so areas below the x-axis count as negative.
4. To evaluate:
- Find the antiderivative \(F(x)\).
- Substitute the upper limit \(b\) into \(F(x)\).
- Substitute the lower limit \(a\) into \(F(x)\).
- Subtract \(F(a)\) from \(F(b)\).
5. This process gives the exact accumulated value of \(f(x)\) over \([a,b]\).