Primitive of Function of a x + b

Theorem

$\ds \int \map F {a x + b} \rd x = \frac 1 a \int \map F u \rd u$

where $u = a x + b$.


Proof

\(\ds u\) \(=\) \(\ds a x + b\)
\(\ds \leadsto \ \ \) \(\ds \frac {\d u} {\d x}\) \(=\) \(\ds a\) Derivative of Function of Constant Multiple: Corollary
\(\ds \leadsto \ \ \) \(\ds \int \map F {a x + b} \rd x\) \(=\) \(\ds \int \frac {\map F u} a \d u\) Primitive of Composite Function
\(\ds \) \(=\) \(\ds \frac 1 a \int \map F u \rd u\) Primitive of Constant Multiple of Function

$\blacksquare$


Sources

  • 1945: A. Geary, H.V. Lowry and H.A. Hayden: Advanced Mathematics for Technical Students, Part I ... (previous) ... (next): Chapter $\text {III}$: Integration: Three rules for integration: $\text {III}$
  • 1953: L. Harwood Clarke: A Note Book in Pure Mathematics ... (previous) ... (next): $\text {II}$. Calculus: Integration
  • 1968: Murray R. Spiegel: Mathematical Handbook of Formulas and Tables ... (previous) ... (next): $\S 14$: Important Transformations: $14.49$
  • 2009: Murray R. Spiegel, Seymour Lipschutz and John Liu: Mathematical Handbook of Formulas and Tables (3rd ed.) ... (previous) ... (next): $\S 16$: Indefinite Integrals: Important Transformations: $16.49.$