作业帮 > 数学 > 作业

分式化简求值 (10 18:51:4)

来源:学生作业帮 编辑:拍题作业网作业帮 分类:数学作业 时间:2024/11/01 07:29:39
分式化简求值 (10 18:51:4)
1.(x^2-2x分之1减去x^2-4x+4分之1)/x^2-2x分之2,其中x=1.
2.(a+1分之2加a^2-1分之a+2)/a-1分之a,其中a=根号3-1
3.[x^2-1分之x^2-2x+1加x分之1]/x+1分之1,其中x=3
4.已知M=x^2-y^2分之2xy ,  N=x^2-y^2分之x^2+y^2用“+”或“-”连接M,N.M+N  ,   M-N
   请你选择一种进行计算,并化简求值,其中x:y=5:2
[1/(x^2-2x)-1/(x^2-4x+4)]/[2/(x^2-2x)]
=[1/x(x-2)-1/(x-2)^2]/[2/x(x-2)]
=1/(x-2)[1/x-1/(x-2)]*x(x-2)/2
=[1/x-1/(x-2)]*x/2
=[(x-2)/x(x-2)-x/x(x-2)]*x/2
=[(x-2-x)/x(x-2)]*x/2
=[-2/x(x-2)]*x/2
=-1/(x-2)
=-1/(1-2)
=1
[2/(a+1)+(a+2)/(a^2-1)]/[a/(a-1)]
=[2/(a+1)+(a+2)/(a-1)(a+1)]/[a/(a-1)]
=1/(a+1)[2+(a+2)/(a-1)]/[a/(a-1)]
=1/(a+1)[2+(a+2)/(a-1)]*(a-1)/a
=[2+(a+2)/(a-1)]/a
=[2(a-1)/(a-1)+(a+2)/(a-1)]/a
=[2(a-1)+(a+2)]/(a-1)]/a
=[2a-2+a+2]/(a-1)]/a
=[3a/(a-1)]/a
=3/(a-1)
=3/(√3-1-1)
=3/(√3-2)
=3(√3+2)/(√3-2)(√3+2)
=-3(√3+2)
=-3√3-6
[(x^2-2x+1)/(x^2-1)+1/x]/[1/(x+1)]
=[(x-1)^2/(x-1)(x+1)+1/x]*(x+1)
=[(x-1)/(x+1)+1/x]*(x+1)
=[x(x-1)/x(x+1)+(x+1)/x(x+1)]*(x+1)
=(x^2-x+x+1)/x(x+1)*(x+1)
=(x^2+1)/x
=(3^2+1)/3
=10/3
M+N =2xy/(x^2-y^2)+(x^2+y^2)/(x^2-y^2)
=(x^2+y^2+2xy)/(x^2-y^2)
=(x+y)^2/(x-y)(x+y)
=(x+y)/(x-y)
=(x/y+1)/(x/y-1)
=(5/2+1)/(5/2-1)
=(7/2)/(3/2)
=7/3
M-N =2xy/(x^2-y^2)-(x^2+y^2)/(x^2-y^2)
=(-x^2-y^2+2xy)/(x^2-y^2)
=-(x-y)^2/(x-y)(x+y)
=-(x-y)/(x+y)
=-(x/y-1)/(x/y+1)
=-(5/2-1)/(5/2+1)
=-(3/2)/(7/2)
=-3/7