已知x的2次方-x-2分之3x+4
来源:学生作业帮助网 编辑:作业帮 时间:2024/06/06 03:04:51
∵X+1/X=3∴(X+1/X)^2=9∴X^2+2+1/X^2=9∴X^2+1/X^2=7∴X^2/(X^4+X^2+1)=1/(X^2+1+1/X^2)=1/(7+1)=1/8
∵x²-3x+1=0∴x²+1=3x(x²+1)×1/x=3x×1/xx²×1/x+1×1/x=3∴x+(1/x)=3∴[x+(1/x)]²=3
因为x²-3x+1=0两边同除以x得:x-3+1/x=0,即x+1/x=3两边平方得::x²+2*x*1/x+1/x²=9即x²+1/x²=7再两边平
x^2+1=3x两边平方x^4+2x^2+1=9x^2x^4+1=7x^2两边除以x^2x^2+1/x^2=7
(3x-4)/(x^2-5x+4)(1)要使分式有意义即x^2-5x+4≠0(x-4)(x-1)≠0x≠4且x≠1(2)要使分式无意义即x^2-5x+4=0(x-4)(x-1)=0x=4或x=1(3)
x+1/x=3x2+1=3x平方x^4+2x2+1=9x2两边减去x2x^4+x2+1=8x2所以x2/(x^4+x2+1)=1/8
(x-1)(x-2)分之3x-4=x-1分之A+x-2分之B同乘以x-1,令x=1得A=1,同乘以x-2,令x=2得B=2所以(A-B)的2012次方=(-1)的2012次方=1
x+1/x=3x²+1=3x平方x^4+2x²+1=9x²两边减去x²x^4+x²+1=8x²所以x²/(x^4+x²+
x+9y=y-3x4x=-8yx=-2y则x²=4y²所以原式=(4y²-y²)/(4y²+y²)=3y²/5y²=3/
①∵(x^4+x²+1)/x²=x²+1+1/x²∴原式=1/(x²+1+1/x²)②∵1/x-1/y=(y-x)/xy=3∴x-xy-y=
1、x²+x²分之1=(x²-2+x²分之1)+2=(x-x分之1)²+2=5²+2=25+2=272、x的4次方+x的4次方分之1=(x的
x^(1/2)+x^(-1/2)=3求x^2+x^(-2)-(x^(3/2)+x^(-3/2))/2-3解:x^(1/2)+x^(-1/2)=3两边平方,得x+x^(-1)+2=9即x+x^(-1)=
f(x)=a^x+(x-2)/(x+1)在(-1,正无穷)上取点(x1,0)(x2,0),且x1>x2则f(x1)-f(x2)=a^x1-a^x2+(x1-x2)/[(x1+1)(x2+1)]因为x1
x+x^-1=4两边平方x²+2+x-=6x²+x-²=14所以原式=2*14=28x+y=2xy=-3则x²+y²=(x+y)²-2xy=
因为x的2次方-3x-1=0两边同除以x得:x-3-1/x=0所以x-1/x=3两边平方得:x²-2+1/x²=9所以x²+1/x²=11
原式=-(x+3)(x-3)/(x+2)(x-2)×(x+2)(x-1)/(x-1)(x-3)=-(x+3)(x-3)/(x+2)(x-2)×(x+2)/(x-3)=-(x+3)/(x-2)再问:4-
本题应该先化简再求值,但后面题目具有歧义性,无法做.
2x-2/x=32x^2-3x-2=0x1=-1/2x2=2x^4+1/x^4=1/16+16=157/16x^4+1/x^4=16+1/16=157/16
①∵x²+3x-1=0∴x+3-1/x=0∴x-1/x=-3②(1+1/x)²=(1-1/x)²+4=(-3)²+4=13