2021-007

Choose the incorrect alternative below:

1. If \( f(x) = 2x^{−2} \), then \( f'(x) = −4x^{−1} \)
2. If \( f(x) = xe^x \), then \( f'(x) = (x+1)e^x \)
3. If \( f(x) = \sqrt{x^2+1} \), then \( f'(x) = x / \sqrt{x^2+1} \)
4. If \( f(x) = x^{−1} \), then \( \int 𝑓 = \ln x + C \)
   
5. none of the above

Original idea by: Mauricio Schiezaro