sin(a+π/4)/sin2a+cos2a+1
=(sina*sin45+cosa*cos45)/(2*sina*cosa)+(1-2sina^2)+1
=(√15/2*√2/2+(-1/4)√2/2)/(2*√15/2*(-1/4))+(1-2*(√15/2)^2)+1
=计算结果你自己来吧...