分式和2次根式问题(1)若X+1/X=3,则X^2+1/X^2=?(2)已知X,Y满足X=Y/Y+2,用含X的代数式表示Y,得Y=?也要有过程.
来源:学生作业帮助网 编辑:作业帮 时间:2024/07/03 15:39:26
![分式和2次根式问题(1)若X+1/X=3,则X^2+1/X^2=?(2)已知X,Y满足X=Y/Y+2,用含X的代数式表示Y,得Y=?也要有过程.](/uploads/image/z/2606701-13-1.jpg?t=%E5%88%86%E5%BC%8F%E5%92%8C2%E6%AC%A1%E6%A0%B9%E5%BC%8F%E9%97%AE%E9%A2%98%281%29%E8%8B%A5X%2B1%2FX%3D3%2C%E5%88%99X%5E2%2B1%2FX%5E2%3D%3F%282%29%E5%B7%B2%E7%9F%A5X%2CY%E6%BB%A1%E8%B6%B3X%3DY%2FY%2B2%2C%E7%94%A8%E5%90%ABX%E7%9A%84%E4%BB%A3%E6%95%B0%E5%BC%8F%E8%A1%A8%E7%A4%BAY%2C%E5%BE%97Y%3D%3F%E4%B9%9F%E8%A6%81%E6%9C%89%E8%BF%87%E7%A8%8B.)
分式和2次根式问题(1)若X+1/X=3,则X^2+1/X^2=?(2)已知X,Y满足X=Y/Y+2,用含X的代数式表示Y,得Y=?也要有过程.
分式和2次根式问题
(1)若X+1/X=3,则X^2+1/X^2=?
(2)已知X,Y满足X=Y/Y+2,用含X的代数式表示Y,得Y=?
也要有过程.
分式和2次根式问题(1)若X+1/X=3,则X^2+1/X^2=?(2)已知X,Y满足X=Y/Y+2,用含X的代数式表示Y,得Y=?也要有过程.
1
x+1/x=3,两边平方,
x^2+1/x^2+2=9
x^2+1/x^2=7
2
X=Y/(Y+2),
x(y+2)=y
xy+2x=y
2x=y(1-x)
y=2x/(1-x)
(1)若X+1/X=3,则X^2+1/X^2=? 给出过程
x+1/x=3
平方得
x²+2*x*1/x+1/x²=3²
x²+2+1/x²=9
x²+1/x²=7
(2)已知X,Y满足X=Y/Y+2,用含X的代数式表示Y,得Y=?
x=y/(y+2)
两边取倒数是...
全部展开
(1)若X+1/X=3,则X^2+1/X^2=? 给出过程
x+1/x=3
平方得
x²+2*x*1/x+1/x²=3²
x²+2+1/x²=9
x²+1/x²=7
(2)已知X,Y满足X=Y/Y+2,用含X的代数式表示Y,得Y=?
x=y/(y+2)
两边取倒数是
1/x=(y+2)/y
1/x=1+2/y
1/x-1=2/y
(1-x)/x=2/y
再取倒数
x/(1-x)=y/2
所以y=2x/(1-x)
收起
(1)配方法: X^2+1/X^2 =(X+1/X)^2-2=7
(2)由X=Y/(Y+2)得
X(Y+2)=Y
(1-X)Y=2X
所以
Y=2X/(1-X)