Sin t=5/13, пи /2<t<пи , найти sin2t

Question

Sin t=5/13, пи /2

Answer 1

Cost = - √ ( 169/169 - 25/169) = - √144/169 = - 12/13
sin2t = 2 *sint * cost = 2 * (5/13)* (-12/13) = - 120/169