Răspuns :
sin a=1/3, a∈cadr.1
cos a=[tex] \sqrt{1- sin^{2}a }= \sqrt{1- \frac{1}{9} } = \frac{2 \sqrt{2} }{3} [/tex]
ctga=[tex] \frac{cosa}{sina}= \frac{ \frac{1}{3} }{ \frac{2 \sqrt{2} }{3} } =[tex] \frac{1}{2 \sqrt{2} } [/tex]
cos a=[tex] \sqrt{1- sin^{2}a }= \sqrt{1- \frac{1}{9} } = \frac{2 \sqrt{2} }{3} [/tex]
ctga=[tex] \frac{cosa}{sina}= \frac{ \frac{1}{3} }{ \frac{2 \sqrt{2} }{3} } =[tex] \frac{1}{2 \sqrt{2} } [/tex]
