Rešite cosbeta

$$\cos \beta$$

Odvajajte w.r.t. β

$$-\sin(\beta )$$

Koraki z uporabo definicije odvoda

Za funkcijo f\left(x\right) je odvod limita funkcije \frac{f\left(x+h\right)-f\left(x\right)}{h}, saj gre h v 0, če ta limita obstaja.

$$\frac{\mathrm{d}}{\mathrm{d}\beta }(\cos(\beta ))=\left(\lim_{h\to 0}\frac{\cos(\beta +h)-\cos(\beta )}{h}\right)$$

Uporabite formulo za kosinus vsote.

$$\lim_{h\to 0}\frac{\cos(h+\beta )-\cos(\beta )}{h}$$

Faktorizirajte \cos(\beta ).

$$\lim_{h\to 0}\frac{\cos(\beta )\left(\cos(h)-1\right)-\sin(\beta )\sin(h)}{h}$$

Znova napišite limito.

$$\left(\lim_{h\to 0}\cos(\beta )\right)\left(\lim_{h\to 0}\frac{\cos(h)-1}{h}\right)-\left(\lim_{h\to 0}\sin(\beta )\right)\left(\lim_{h\to 0}\frac{\sin(h)}{h}\right)$$

Uporabite dejstvo, da je \beta konstanta, kadar računate limite, saj gre h v 0.

$$\cos(\beta )\left(\lim_{h\to 0}\frac{\cos(h)-1}{h}\right)-\sin(\beta )\left(\lim_{h\to 0}\frac{\sin(h)}{h}\right)$$

Limita \lim_{\beta \to 0}\frac{\sin(\beta )}{\beta } je 1.

$$\cos(\beta )\left(\lim_{h\to 0}\frac{\cos(h)-1}{h}\right)-\sin(\beta )$$

Če želite ovrednotiti limite \lim_{h\to 0}\frac{\cos(h)-1}{h}, najprej pomnožite števec in imenovalec s \cos(h)+1.

$$\left(\lim_{h\to 0}\frac{\cos(h)-1}{h}\right)=\left(\lim_{h\to 0}\frac{\left(\cos(h)-1\right)\left(\cos(h)+1\right)}{h\left(\cos(h)+1\right)}\right)$$

Pomnožite \cos(h)+1 s/z \cos(h)-1.

$$\lim_{h\to 0}\frac{\left(\cos(h)\right)^{2}-1}{h\left(\cos(h)+1\right)}$$

Uporabite Pitagorovo identiteto.

$$\lim_{h\to 0}-\frac{\left(\sin(h)\right)^{2}}{h\left(\cos(h)+1\right)}$$

Znova napišite limito.

$$\left(\lim_{h\to 0}-\frac{\sin(h)}{h}\right)\left(\lim_{h\to 0}\frac{\sin(h)}{\cos(h)+1}\right)$$

Limita \lim_{\beta \to 0}\frac{\sin(\beta )}{\beta } je 1.

$$-\left(\lim_{h\to 0}\frac{\sin(h)}{\cos(h)+1}\right)$$

Uporabite dejstvo, da je funkcija \frac{\sin(h)}{\cos(h)+1} zvezna pri 0.

$$\left(\lim_{h\to 0}\frac{\sin(h)}{\cos(h)+1}\right)=0$$

Vstavite vrednost 0 v izraz \cos(\beta )\left(\lim_{h\to 0}\frac{\cos(h)-1}{h}\right)-\sin(\beta ).

$$-\sin(\beta )$$

Ovrednoti

$$\cos(\beta )$$