答：
β=π.
a*b
=(tan(α+π/4),-1)(cosα,2)
=cosα×tan(α+π/4)-2=m.
{2(cosα)^2+sin[2(α+β)]}/(cosα-sinα)
={2(cosα)^2+sin[2(α+π)]}/(cosα-sinα)
=[2(cosα)^2+sin(2α)]/(cosα-sinα)
=[2(cosα)^2+2sinαcosα]/(cosα-sinα)
=2cosα(cosα+sinα)/(cosα-sinα)
=2cosα×(1+tanα)/(1-tanα)
=2cosα×tan(α+π/4)
=2(m+2)