x^2 + (根號2)y = (根號3),y^2 + (根號2)x = (根號3)。且x不等于y, 求 (y/x)+ (x/y).
熱心網友
x^2+根號2*y=根號3 (1),y^2+根號2*x=根號3 (2),(1)-(2)化簡得x+y=根號2 (3),(1)+(2)變形:(x+y)^2-2xy+根號2(x+y)=2根號3 (4),把(3)代入(4)得xy=2-根號3.(y/x)+(x/y)=(x+y)^2/xy-2=2+2根號3
熱心網友
x^2+2^0.5*y=3^0.5-----(1) y^2+2^0.5*x=3^0.5-----(2) (1)-(2): x^2-Y^2=2^0.5(x-y) x+y=2^0.5 (1)+(2): x^2+y^2+2^0.5(x+y)=2*3^0.5 x^2+y^=2(3^0.5-1) xy=0.5*[(x+y)^2-(x^2+y^2)] =2-3^0.5 x/y+y/x=(x^2+y^2)/(x*y) =2*(3^0.5-1)/(2-3^0.5) =2+2*3^(1/2)
熱心網友
x^2 + (根號2)y = (根號3)---------(1)y^2 + (根號2)x = (根號3)---------(2)由(1)-(2)得:(x^2-y^2)+((根號2)y-(根號2)x)=0→(x-y)(x+y-(根號2))=0由于x不等于y, 故x+y-(根號2)=0,即得:x+y=根號2---------(3)由(1)+(2)得:(x^2+y^2)+((根號2)y+(根號2)x)=2(根號3)→((x+y)^2-2xy)+(根號2)(x+y)=2(根號3)代入(3)式得:2-2xy+2=2(根號3)故:xy=2-根號3 ---------(4)得:x^2+y^2=(x+y)^2-2xy=4-2(2-根號3)=2*根號3所以(y/x)+ (x/y)=(x^2+y^2)/xy=2*根號3/(2-根號3)=2*根號3(2+根號3)=6+4*根號3。
熱心網友
x^2 + (根號2)y = (根號3)---------(1)y^2 + (根號2)x = (根號3)---------(2)(1)-(2)有:x^2-y^2=根號2(x-y)因為x不等于y所以x+y=根號2--------(3)(1)+(2)有:x^2 + y^2 + (根號2)(x +y)=2根號3配方得(x+ y)^2 + (根號2)(x +y)-2xy=2根號3---------(4)把(3)代入(4)得xy=2-根號3故(y/x)+ (x/y)=(x^2 + y^2)/xy=((x+ y)^2-2xy)/xy=3+2根號3