Question

数学题。 18题

Answer 1

• 设X1=Sin@(找不到那个符号就用@代替了）设X2=Cos@

• (Sin@平方/Sin-Cos@)+Cos@/(1-tan@)=X1平方/(X1-X2)+X2/（1-tan@)=X1平方/（X1-X2)-X2平方/（X1-X2)=X1+X2=-b/a=（根号3+1）/2

• 希望对你有帮助
  

Answer 2

2x^2-(√3+1)x+m=0
sinθ+cosθ=(√3+1)/2
sinθcosθ=m/2
sin^2θ/(sinθ-cosθ)+cosθ/(1-tanθ)
=sin^2θ/(sinθ-cosθ)-cos^2θ/(sinθ-cosθ)
=(sin^2θ-cos^2θ)/(sinθ-cosθ)
=sinθ+cosθ
=(√3+1)/2

追问

cos²这一步没看懂

忽然又懂了😂