Sint=-3/53п/2<t<2п Найти cost, tgt, ctgt

Решите задачу:

$sint=- \frac{3}{5}, \frac{3 \pi }{2} \ \textless \ t\ \textless \ 2 \pi \\ sin^2t+cos^2t=1 \\ cos^2t=1-sin^2t \\ cos^2t=1- \frac{9}{25} \\ cos^2t= \frac{16}{25} \\ cost= \frac{4}{5} \\ \\ tgt= \frac{sint}{cost} =-\frac{3}{5}:\frac{4}{5}=-\frac{3}{5}* \frac{5}{4} =- \frac{3}{4} \\ \\ ctgt= \frac{1}{ tgt} =1:(- \frac{3}{4})=- \frac{4}{3} =-1 \frac{1}{3}$