Primitivele funcţiilor exponenţiale

De la Wikipedia, enciclopedia liberă

Acest articol face parte din seria de articole
Primitive ale diferitelor funcţii
Tabel de integrale
Raţionale
Logaritmice
Exponenţiale
Iraţionale
Trigonometrice
Hiperbolice
Invers trigonometrice
Hiperbolice reciproce

Următorul articol este o listă de integrale (primitive) de funcţii exponenţiale. Pentru o listă cu mai multe integrale, vezi tabel de integrale şi lista integralelor.

\int e^{cx}\;dx = \frac{1}{c} e^{cx}
\int a^{cx}\;dx = \frac{1}{c \ln a} a^{cx} \qquad\mbox{(for } a > 0,\mbox{ }a \ne 1\mbox{)}
\int xe^{cx}\; dx = \frac{e^{cx}}{c^2}(cx-1)
\int x^2 e^{cx}\;dx = e^{cx}\left(\frac{x^2}{c}-\frac{2x}{c^2}+\frac{2}{c^3}\right)
\int x^n e^{cx}\; dx = \frac{1}{c} x^n e^{cx} - \frac{n}{c}\int x^{n-1} e^{cx} dx
\int\frac{e^{cx}\; dx}{x} = \ln|x| +\sum_{i=1}^\infty\frac{(cx)^i}{i\cdot i!}
\int\frac{e^{cx}\; dx}{x^n} = \frac{1}{n-1}\left(-\frac{e^{cx}}{x^{n-1}}+c\int\frac{e^{cx} }{x^{n-1}}\,dx\right) \qquad\mbox{(for }n\neq 1\mbox{)}
\int e^{cx}\ln x\; dx = \frac{1}{c}e^{cx}\ln|x|-\operatorname{Ei}\,(cx)
\int e^{cx}\sin bx\; dx = \frac{e^{cx}}{c^2+b^2}(c\sin bx - b\cos bx)
\int e^{cx}\cos bx\; dx = \frac{e^{cx}}{c^2+b^2}(c\cos bx + b\sin bx)
\int e^{cx}\sin^n x\; dx = \frac{e^{cx}\sin^{n-1} x}{c^2+n^2}(c\sin x-n\cos x)+\frac{n(n-1)}{c^2+n^2}\int e^{cx}\sin^{n-2} x\;dx
\int e^{cx}\cos^n x\; dx = \frac{e^{cx}\cos^{n-1} x}{c^2+n^2}(c\cos x+n\sin x)+\frac{n(n-1)}{c^2+n^2}\int e^{cx}\cos^{n-2} x\;dx
\int x e^{c x^2 }\; dx= \frac{1}{2c} \;  e^{c x^2}
\int {1 \over \sigma\sqrt{2\pi} }\,e^{-{(x-\mu )^2 / 2\sigma^2}}\; dx= \frac{1}{2 \sigma} (1 + \mbox{erf}\,\frac{x-\mu}{\sigma \sqrt{2}})
\int e^{x^2}\,dx = e^{x^2}\left( \sum_{j=0}^{n-1}c_{2j}\,\frac{1}{x^{2j+1}} \right )+(2n-1)c_{2n-2} \int \frac{e^{x^2}}{x^{2n}}\;dx  \quad \mbox{valabil pentru } n > 0,
unde c_{2j}=\frac{ 1 \cdot 3 \cdot 5 \cdots (2j-1)}{2^{j+1}}=\frac{2j\,!}{j!\, 2^{2j+1}} \ .
\int_{-\infty}^{\infty} e^{-ax^2}\,dx=\sqrt{\pi \over a} (Integrala gaussiană)
\int_{-\infty}^{\infty} x e^{-a(x-b)^2}\,dx=b \sqrt{\pi \over a}
\int_{-\infty}^{\infty} x^2 e^{-ax^2}\,dx=\frac{1}{2} \sqrt{\pi \over a^3}
\int_{0}^{\infty} x^{2n} e^{-{x^2}/{a^2}}\,dx=\sqrt{\pi} {(2n)! \over {n!}} {\left (\frac{a}{2} \right)}^{2n + 1}
\int_{-\infty}^{\infty} e^{-{x^2}/{a^2}} \cos bx\,dx=a \sqrt{\pi}(\sin{a^2 b^2 \over 4}+\cos{a^2 b^2\over 4})
\int_{0}^{2 \pi} e^{x \cos \theta} d \theta = 2 \pi I_{0}(x) (I0 este funcţia Bessel de speţa I modificată)
\int_{0}^{2 \pi} e^{x \cos \theta + y \sin \theta} d \theta = 2 \pi I_{0} \left( \sqrt{x^2 + y^2} \right)
\int_{0}^{\infty} x^a e^{-bx} dx = \frac{a!}{b^{a+1}}