已知X+Y=3,XY=-1,求2(X-Y)^4-9(X-Y)^2+12XY_数学解答

已知X+Y=3,XY=-1,求2(X-Y)^4-9(X-Y)^2+12XY

人气：360 ℃　时间：2020-06-19 09:58:59

解答

X+Y=3
(x+y)^2=9
(x-y)^2+4xy=9
(x-y)^2=9-4(-1)=13
2(X-Y)^4-9(X-Y)^2+12XY
=2*13^2-9*13+12(-1)
=338-117-12
=209