Respostas

2013-11-19T21:46:26-02:00
Senx² + cosx² = 1
( \frac{3  }{5} )^{2} + cosx² = 1
 \frac{9}{25} + cosx² = 1
cosx² = 1 -  \frac{9}{25}
cosx² =  \frac{16}{25}
cosx =  \sqrt{ \frac{16}{25} }
cosx =  \frac{4}{5}


tgx = senx / cosx
tgx =  \frac{ \frac{3}{5} }{ \frac{4}{5} }
tgx =  \frac{15}{20}

etc, etc......