It is known that sin α - sin β = 1 / 4, cos α + cos β = 1 / 3 I got the answer - 163 / 288, but the teacher gave me a little red fork

It is known that sin α - sin β = 1 / 4, cos α + cos β = 1 / 3 I got the answer - 163 / 288, but the teacher gave me a little red fork

sinα-sinβ=1/4,cosα+cosβ=1/3
Add the squares separately to get
2+2(cosαsinβ-sinαcosβ)=1/16+1/9
The solution is cos α sin β - sin α cos β = - 263 / 288
That is cos (α + β) = - 263 / 288
You only miscalculated one digit, that is, the hundred should be 2 instead of 1