Question

I need help with exercise b.

Answer 1

$\bf sin(-t)=\cfrac{5}{7}\implies -sin(t)=\cfrac{5}{7}\implies sin(t)=-\cfrac{5}{7}\\\\ -------------------------------\\\\ csc(t)\implies \cfrac{1}{sin(t)}\implies \cfrac{1}{-\frac{5}{7}}\implies \cfrac{\frac{1}{1}}{-\frac{5}{7}}\implies \cfrac{1}{1}\cdot -\cfrac{7}{5}\implies -\cfrac{7}{5}$