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Cu ce este egal sinusul si cosinusul de 30 grade, 45, 60, 120. 



Răspuns :

sin<30= 1/2
cos<30= √3/2

sin<45= √2/2
cos<45=√2/2

sin<60=√3/2
cos<60=1/2

sin<120=√3/2
cos<120= -1/2
sin30=cos60=1/2
sin45=cos45=radical din 2/2
sin60=cos30=radical3/2
sin120=sin(60+60)=sin60cos60+sin60cos60=2*1/2*radical3/2=radical3/2
cos120=cos(60+60)=cos60cos60-sin60sin60=1/4-3/4=-1/2