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Integration by Parts

Evaluate I_n(b)=integral_0^b x^n exp(x) dx using the reduction formula.

Free theory article

Evaluate I_n(b)=integral_0^b x^n exp(x) dx using the reduction formula.

Concept & interpretation

Integration by parts is a powerful technique in calculus that is derived from the product rule for differentiation. It allows us to evaluate the integral of a product of functions by transforming it into another, hopefully simpler, integral.

Interactive Experiment

You can explore this reduction process using the Integration by Parts module.

  1. Set Power n to 2.
  2. Set Upper bound b to 1.
  3. Observe the full reduction ledger. It shows the calculated values for I2, I1, and I0 sequentially.
  4. Note how the boundary term bk eb and remainder term k Ik-1 dynamically update the value of Ik for each step.
  5. Set Power n to 0 and Upper bound b to 1. The single base row is e − 1, approximately 1.71828182846; no negative power is evaluated.
  6. Set Upper bound b to 0, then set Power n to 3. Every displayed integral is exactly 0 and the ledger still ends at I0.
  7. Keep Power n = 3 and set Upper bound b to 2. Read 2e2 + 6, approximately 20.7781121979.
  8. Clear Upper bound b to see its error and hidden reduction results. Restore 1, pan the curve, then choose Reset view; the two input values remain unchanged.
Read the full free theory article