Exercise · ZW-INTEGRATION-BY-PARTS-006 · ★★☆ Intermediate
Compute \(\displaystyle\int x \cos {x}\,dx\).
Choose one option.
Show answer
- B. \(x \sin {x} + \cos {x} + C\)
Explanation
Choose \(u=x,\ dv=\cos x\,dx\) and apply \(\int u\,dv=uv-\int v\,du\). The result is \(x \sin {x} + \cos {x} + C\). Check: \((x \sin {x} + \cos {x})'=x \cos {x}\).
Review the concept: Integration by parts
Integration by parts is a technique for integrating products of functions, derived from the product rule. It transforms \(\int u\,dv\) into \(uv-\int v\,du\).
\[\int u\,dv=uv-\int v\,du\]
More practice problems: integration by parts
- ZW-INTEGRATION-BY-PARTS-001 When computing ∫ x e^x dx by parts, which choice of u and dv is suitable?
- ZW-INTEGRATION-BY-PARTS-002 Compute ∫ x e^x dx.
- ZW-INTEGRATION-BY-PARTS-003 Compute ∫ x sin x dx.
- ZW-INTEGRATION-BY-PARTS-004 Compute ∫ ln (x ) dx.
- ZW-INTEGRATION-BY-PARTS-005 Compute ∫ x^2 e^x dx.
- ZW-INTEGRATION-BY-PARTS-007 What is the integration by parts formula?
- ZW-INTEGRATION-BY-PARTS-008 According to the LIATE rule, which family of functions should be chosen first as u?
- ZW-INTEGRATION-BY-PARTS-009 Which choice of u and dv is suitable for ∫ xln x dx?