已知x的2次方减x减2分之3x 4
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已知x的平方减4x加1等于0,x-4+1/x=0x+1/x=4x^2+2+1/x^2=16x^2+1/x^2=14x的4次方加x的2次方+1分之x²的值=1/(x^2+1+1/x^2)=1/
∵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
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
2^(x+3)×3^(x+3)=36^(x-2)(2×3)^(x+3)=(6^2)^(x-2)6^(x+3)=6^^(2x-4)x+3=2x-4x=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)
x²-5x+1=0两边同时除以xx+1/x=5两边平方x²+2+1/x²=25x²+1/x²=23两边平方x四次方+1/x四次方=527
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=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+
同时取对数令:xlg3=ylg4=zlg6=m则1/x=lg3/m1/y=lg4/m1/z=lg6/m1/z-1/x=(lg6-lg3)/m=lg2/m1/(2y)=(1/2)lg4/m=lg2/m得
x+9y=y-3x4x=-8yx=-2y则x²=4y²所以原式=(4y²-y²)/(4y²+y²)=3y²/5y²=3/
(x²-8)/(x-3)-1/(x-3)=[(x²-8)-1]/(x-3)=[x²-9]/(x-3)=[(x+3)(x-3)]/(x-3)=x+3
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
^表示次方x^2-5x+1=0求x^2+1/x^2和x^4+1/x^4答x^2-5x+1=0左右同除x得x-5+1/x=0x+1/x=5两边平方得x^2+2+1/x^2=25移项得x^2+1/x^2=
(1/3)^(-x)=2.即:3^x=2.所以:(3^x)^4=((3^2)^x)^2=9^2x=2^4=16.1/3^(-y)=5.即:3^y=5.所以:(3^y)^2=(3^2)^y=9^y=25
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