📝 Two Methods For Making Substitutions In Definite Integrals

Q1. When evaluating \(\int_0^{\pi} \sin x \, dx\), which substitution leads directly to the antiderivative?

💡 Difficulty: easy | ✅ Correct: B

Q2. A student evaluates \(\int_1^3 (2x + 5) \, dx\) by letting \(u = 2x + 5\). Which step is missing in the substitution process?

💡 Difficulty: medium | ✅ Correct: A

Q3. When evaluating \(\int_0^2 (x^3 + 3x) \, dx\) by the substitution \(u = x^2\), which error is introduced?

💡 Difficulty: hard | ✅ Correct: C