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Funktion $$$\cos{\left(e^{t} \right)}$$$ derivaatta
Aiheeseen liittyvät laskurit: Logaritmisen derivoinnin laskin, Vaiheittainen implisiittisen derivoinnin laskin
Syötteesi
Määritä $$$\frac{d}{dt} \left(\cos{\left(e^{t} \right)}\right)$$$.
Ratkaisu
Funktio $$$\cos{\left(e^{t} \right)}$$$ on kahden funktion $$$f{\left(u \right)} = \cos{\left(u \right)}$$$ ja $$$g{\left(t \right)} = e^{t}$$$ yhdistelmä $$$f{\left(g{\left(t \right)} \right)}$$$.
Sovella ketjusääntöä $$$\frac{d}{dt} \left(f{\left(g{\left(t \right)} \right)}\right) = \frac{d}{du} \left(f{\left(u \right)}\right) \frac{d}{dt} \left(g{\left(t \right)}\right)$$$:
$${\color{red}\left(\frac{d}{dt} \left(\cos{\left(e^{t} \right)}\right)\right)} = {\color{red}\left(\frac{d}{du} \left(\cos{\left(u \right)}\right) \frac{d}{dt} \left(e^{t}\right)\right)}$$Kosinin derivaatta on $$$\frac{d}{du} \left(\cos{\left(u \right)}\right) = - \sin{\left(u \right)}$$$:
$${\color{red}\left(\frac{d}{du} \left(\cos{\left(u \right)}\right)\right)} \frac{d}{dt} \left(e^{t}\right) = {\color{red}\left(- \sin{\left(u \right)}\right)} \frac{d}{dt} \left(e^{t}\right)$$Palaa alkuperäiseen muuttujaan:
$$- \sin{\left({\color{red}\left(u\right)} \right)} \frac{d}{dt} \left(e^{t}\right) = - \sin{\left({\color{red}\left(e^{t}\right)} \right)} \frac{d}{dt} \left(e^{t}\right)$$Eksponenttifunktion derivaatta on $$$\frac{d}{dt} \left(e^{t}\right) = e^{t}$$$:
$$- \sin{\left(e^{t} \right)} {\color{red}\left(\frac{d}{dt} \left(e^{t}\right)\right)} = - \sin{\left(e^{t} \right)} {\color{red}\left(e^{t}\right)}$$Näin ollen, $$$\frac{d}{dt} \left(\cos{\left(e^{t} \right)}\right) = - e^{t} \sin{\left(e^{t} \right)}$$$.
Vastaus
$$$\frac{d}{dt} \left(\cos{\left(e^{t} \right)}\right) = - e^{t} \sin{\left(e^{t} \right)}$$$A