Integralen av $$$s^{2} \sin{\left(x^{2} \right)}$$$ med avseende på $$$x$$$

Bestäm $$$\int s^{2} \sin{\left(x^{2} \right)}\, dx$$$.

Tillämpa konstantfaktorregeln $$$\int c f{\left(x \right)}\, dx = c \int f{\left(x \right)}\, dx$$$ med $$$c=s^{2}$$$ och $$$f{\left(x \right)} = \sin{\left(x^{2} \right)}$$$:

$${\color{red}{\int{s^{2} \sin{\left(x^{2} \right)} d x}}} = {\color{red}{s^{2} \int{\sin{\left(x^{2} \right)} d x}}}$$

Denna integral (Fresnels sinusintegral) har ingen sluten form:

$$s^{2} {\color{red}{\int{\sin{\left(x^{2} \right)} d x}}} = s^{2} {\color{red}{\left(\frac{\sqrt{2} \sqrt{\pi} S\left(\frac{\sqrt{2} x}{\sqrt{\pi}}\right)}{2}\right)}}$$

Alltså,

$$\int{s^{2} \sin{\left(x^{2} \right)} d x} = \frac{\sqrt{2} \sqrt{\pi} s^{2} S\left(\frac{\sqrt{2} x}{\sqrt{\pi}}\right)}{2}$$

Lägg till integrationskonstanten:

$$\int{s^{2} \sin{\left(x^{2} \right)} d x} = \frac{\sqrt{2} \sqrt{\pi} s^{2} S\left(\frac{\sqrt{2} x}{\sqrt{\pi}}\right)}{2}+C$$

$$$\int s^{2} \sin{\left(x^{2} \right)}\, dx = \frac{\sqrt{2} \sqrt{\pi} s^{2} S\left(\frac{\sqrt{2} x}{\sqrt{\pi}}\right)}{2} + C$$$A