已知x=1根号2y=1+根号2求x²+y²xy2x+2y
已知,x=1-根号2,y=1+根号2,求x²+y²-xy-2x+2y -
答案是:7+4根号2
见图,
答案是:7+4根号2
见图,
9+4√2
∴x+y=2,xy=﹣1,x-y=﹣2√2 ∴x²+y²-xy-2x+2y=﹙x+y﹚²-3xy-2﹙x-y﹚=2²-3×﹙﹣1﹚-2×﹙﹣2√2﹚=4+3+4√2 =7+4√2
已知x=1-根号2,y=1+根号2,求(x+y/1+x-y/1)/x²-xy/2x的值 -
代数式=[(x-y)+(x-y)]/[(x+y)(x-y)]乘以(x-y)x/2x =x/(x+y)将x=1-√2,y=1+√2代入上式得代数式=(1-√2)/(1-√2+1+√2)=(1-√2)/2
解:∵ x=根号2+1,y=根号2-1 ∴ x²+2xy+y² =(x+y)² =(根号2+1+根号2-1)²=(2根号2)² =4×2 = 8
已知x/y=1/2,求x^2+2xy+y^2/x^2-xy+y^2 -
你好解(x^2+2xy+y^2)(x^2-xy+y^2)(x+y)2/(x-y)2 上下同除以y^2 得=(x/y+1)2/(x/y-1)2 =(3/2)2/(1/2)2 =(9/4)(1/4)9 【数学辅导团】为您解答,不理解请追问,理解请及时选为满意回答!*^__^*)谢谢!
解:因为x/y=1/2 所以y=2x ∴x²+2xy+y²/x²-xy-2y²=(x+y)²/(x-2y)(x+y)=(x+y)/(x-2y)=(x+2x)/(x-4x)=3x/(-3x)=-1
已知x=根号2-1/根号2+1,y=根号2+1/根号2-1,求x-y/x2+y2 -
x=√2+1,y=√2-1,则x-y=2,xy=1,(x-y)��=x��+y��-2xy=4则 x��+y��=6所以(x+y)��= x��+y��+2xy=8所以x+y=2√2则 x-y/2x+2y=2是什么。
x=根号2-1 y=根号2+1 x+y=(根号2-1)+(根号2+1)=2根号2 xy=(根号2-1)(根号2+1)2-1=1 x/y+y/x=(x^2+y^2)/(xy)=[(x+y)^2-2xy]/(xy)=[(2根号2)^2-2*1]/1=6