Question

вычеслить
sin(a+b)-3cosa если sina=5/13
cosb=3/5
0

Answer 1

sinβ=√1-9/25=√16/25=4/5     cosα=√1-25/169=√144/169=12/13
sin(α+β)-3cosα=sinαcosβ+sinβcosα-3cosα=5/13*3/5+4/5*12/13-3*12/13=
= 3/13+48/65-.36/13=-9/5=-1.8