Jawabanmu

2014-02-24T19:31:45+07:00
1-cosa =  \frac{9}{25(1+cosa)}
kalikan kedua ruas dengan  1 + cos a, didapat
1-cos^{2}a =  \frac{9}{25}
sin^{2}a =  \frac{9}{25}
sina =  \frac{3}{5}
1-cos^{2}a =  \frac{9}{25}
cos^{2}a =1-  \frac{9}{25}
cos^{2}a =  \frac{16}{25}
cosa =  \frac{4}{5}
sehingga
tana =  \frac{sina}{cosa} = \frac{3/5}{4/5} = \frac{3}{4}

CMIIW :3