tolong bantu no.2 pakai cara

90<a<180 = kuadran II
sin a = 8 / 17
cos a = -15 / 17

>>> 2 sin a + cos a / 3 cos a + 5 sin a
>>> 2 x 8/17 + (-15/17) / 3 x (-15/17) + 5 x 8/17
>>> 16/17 + (-15/17) / (-45/17) + 40/17
>>>(1/17) / (-5/17)
>>> 1/17 x -17/5
>>> -1/5