原帖由 刺身哥 於 2011-10-13 22:31 發表
求解(功課來的@@)
If a and B are the roots of the quadratic equation 4x*+7x-6=0 ,form a quadratic equation in x whose roots are a/(a-2) and B/(B-2)
(我中4= =,不打算修M2了)
α+β=1.75=7/4
αβ=-1.5=-3/2
α/α-2 + β/β-2 = [a(β-2)+ β/(α-2)] / (α-2)(β-2)
= (αβ-2α+αβ-2β) / αβ-2β-2α+4
= 2αβ-2(α+β) / αβ+4-2(α+β)
(α/α-2).(β/β-2)= αβ / αβ+4-2(α+β)
自己sub數