Question

REDUCETI LA PRIMUL CADRAN URMATOARELE VALORI (TRIGONOMETRIE)[tex].cos 865 grade ; \frac{907 \pi }{3} ;tg \frac{601 \pi }3} ;sin \frac{sin 2000 \pi }{11} [/tex]

Answer 1

cos865=cos(720+145)=cos145=cos(180-35)=-cos35 (cos in cadranul  II are semnul -)
In fata celei de a doua fractii nu ai scris functia
$tg\dfrac{601\pi}{3}=tg(200\pi+\dfrac{\pi}{3})=tg\dfrac{\pi}{3}$

$sin\dfrac{2000\pi}{11}=sin(182\pi-\dfrac{2\pi}{11})=-sin\dfrac{2\pi}{11}$ (sin in cadranul IV este negativ)