Determination of Function
General
Grade 12
Question:
$\int f'(x)dx = x \cos \pi x$ and $f(0) = 0$ then value of $f\left(\frac{1}{3}\right)$
Step-by-Step Solution
Key Concept: General
$f(x) + C = x \cos \pi x$<br>$f(0) + C = 0 \cos 0$<br>$0 + C = 0$<br>$\therefore C = 0$<br>$\therefore f(x) = x \cos \pi x$<br>$f\left(\frac{1}{3}\right) = \frac{1}{3} \cos \frac{\pi}{3} \Rightarrow \frac{1}{3} \times \frac{1}{2} = \frac{1}{6}$
Correct Answer: 1/6