Question

sin(a-b)+sinb cosa,если sina=3/5;cos b=-7/15

Answer 1

$sin(a-b)+sin bcos a=sin acos b-sin bcos a+sin bcos a=\=sin acos b=dfrac 35cdotleft(-dfrac7{15}right)=-dfrac{3cdot7}{5cdot15}=-dfrac{7}{5cdot5}=-dfrac7{25}=-0.28$