Definite Integrals

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1 min read Last updated Fri Aug 14 2026 03:05:03 GMT+0000 (Coordinated Universal Time)

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=kabr(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
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