Definite Integrals

Work in progress. This note is still being written and incomplete.

For r(t)=⟨x(t),y(t),z(t)⟩\boldsymbol{r}(t) = \langle x(t), y(t), z(t) \rangle continuous on [a,b][a, b], the definite integral over [a,b][a, b] is defined componentwise:

∫abr(t) dt=⟨∫abx(t) dt,∫aby(t) dt,∫abz(t) dt⟩\int_a^b \boldsymbol{r}(t) \, \text{d}t = \left\langle \int_a^b x(t) \, \text{d}t, \int_a^b y(t) \, \text{d}t, \int_a^b z(t) \, \text{d}t \right\rangle

For r(t)\boldsymbol{r}(t), r1(t)\boldsymbol{r}_1(t), r2(t)\boldsymbol{r}_2(t) continuous on [a,b][a, b] and scalar kk:

  • ∫abkr(t) dt=k∫abr(t) dt\displaystyle\int_a^b k\boldsymbol{r}(t) \, \text{d}t = k \int_a^b \boldsymbol{r}(t) \, \text{d}t
  • ∫ab[r1(t)+r2(t)] dt=∫abr1(t) dt+∫abr2(t) dt\displaystyle\int_a^b [\boldsymbol{r}_1(t) + \boldsymbol{r}_2(t)] \, \text{d}t = \int_a^b \boldsymbol{r}_1(t) \, \text{d}t + \int_a^b \boldsymbol{r}_2(t) \, \text{d}t
Written by October 8, 2026 1 min read
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