已知x-1/x=-2,求x^4+x^2+1分之x^2的值先化简,再求值:(x-y分之1+x+y分之1)除x^2-y^2分之xy,其中x=√3-√2,y=√2.
来源:学生作业帮助网 编辑:作业帮 时间:2024/06/25 03:51:28
![已知x-1/x=-2,求x^4+x^2+1分之x^2的值先化简,再求值:(x-y分之1+x+y分之1)除x^2-y^2分之xy,其中x=√3-√2,y=√2.](/uploads/image/z/120224-56-4.jpg?t=%E5%B7%B2%E7%9F%A5x-1%2Fx%3D-2%2C%E6%B1%82x%5E4%2Bx%5E2%2B1%E5%88%86%E4%B9%8Bx%5E2%E7%9A%84%E5%80%BC%E5%85%88%E5%8C%96%E7%AE%80%2C%E5%86%8D%E6%B1%82%E5%80%BC%EF%BC%9A%28x-y%E5%88%86%E4%B9%8B1%2Bx%2By%E5%88%86%E4%B9%8B1%29%E9%99%A4x%5E2-y%5E2%E5%88%86%E4%B9%8Bxy%2C%E5%85%B6%E4%B8%ADx%3D%E2%88%9A3-%E2%88%9A2%2Cy%3D%E2%88%9A2.)
已知x-1/x=-2,求x^4+x^2+1分之x^2的值先化简,再求值:(x-y分之1+x+y分之1)除x^2-y^2分之xy,其中x=√3-√2,y=√2.
已知x-1/x=-2,求x^4+x^2+1分之x^2的值
先化简,再求值:(x-y分之1+x+y分之1)除x^2-y^2分之xy,其中x=√3-√2,y=√2.
已知x-1/x=-2,求x^4+x^2+1分之x^2的值先化简,再求值:(x-y分之1+x+y分之1)除x^2-y^2分之xy,其中x=√3-√2,y=√2.
1.因为(x^4+x^2+1)/x^2=x^2 +1/x^2 +1 =(x-1/x)^2 +2+1=(-2)^2 +2+1=7
所以x^2/(x^4+x^2+!)=1/7
2.(x-y分之1+x+y分之1)除x^2-y^2分之xy
=[(x+y)+(x-y)]/(x^2-y^2) ÷[xy/(x^2-y^2)]
=2x/(x^2-y^2)÷[xy/(x^2-y^2)]
=2/y
=2/根号2=根号2