1.A=x+2/x√x-1+√x+1/x+√x+1-√x+1
2.B=(1/1-√x-1/1+√x)(1-1/√x)
#Help me
Tìm các số A, B, C để có:
a) (x^2-x+2)/(x-1)^3=[A/(x-1)^3]+[B/(x-1)^2]+C/(x-1)
b) (x^2+2x-1)/(x+1)(x^2+1)=[A/(x-1)]+[(Bx+C)/(x^2+1)]
b=x(1-x)^2)/1+x^2 / [(1-x^2/1-x + x)(1+x^2/1+x - x)] a) rút ngọn b. b) cmb>0 với mọi x>0
Bạn gõ đề ở khung \(\Sigma\) cho đề rõ hơn nhé !
a: \(B=\dfrac{x\left(1-x\right)^2}{1+x^2}:\left[\left(\dfrac{1-x^2}{1-x}+x\right)\left(\dfrac{1+x^2}{1+x}-x\right)\right]\)
\(=\dfrac{x\left(x-1\right)^2}{x^2+1}:\left[\dfrac{1-x^2+x-x^2}{1-x}\cdot\dfrac{1+x^2-x-x^2}{1+x}\right]\)
\(=\dfrac{x\left(x-1\right)^2}{x^2+1}\cdot\dfrac{\left(1-x\right)\left(1+x\right)}{\left(-2x^2+x+1\right)\left(-x+1\right)}\)
\(=\dfrac{x\left(x-1\right)^2}{x^2+1}\cdot\dfrac{\left(x-1\right)\left(x+1\right)}{-\left(x-1\right)\left(2x^2-x-1\right)}\)
\(=\dfrac{-x\left(x-1\right)^2}{x^2+1}\cdot\dfrac{x+1}{2x^2-2x+x-1}\)
\(=\dfrac{-x\left(x-1\right)^2}{x^2+1}\cdot\dfrac{x+1}{\left(x-1\right)\left(2x+1\right)}\)
\(=\dfrac{-x\left(x-1\right)\left(x+1\right)}{\left(2x+1\right)\left(x^2+1\right)}\)
b: Đề này sai rồi bạn ,lỡ x=2 thì nó nhỏ hơn 0 á bạn
Chứng minh đẳng thức:
a, (x^2-2x/2x^2+8-2x^2/8-4x+2x^2-x^3)(1-1/x-2/x^2)=x+1/2x
b, [2/3x-2/x+1(x+1/3x-x-1)]:x-1/x=2x/x-1
c, [2/(x+1)^3(1/x+1)+1/x^2+2x+1(1/x^2+1)]:x-1/x^3=x/x-1
Rút gọn biểu thức
a) A= {[(x√x)-1]\[(√x)-1]+√x}{[(x√x)+1]/[(√x)+1]-√x}
b) B={[ 3/x-(√x)-2] +1/[(√x)+1]}.[(√x)-2]
a) \(A=\left(\dfrac{x\sqrt{x}-1}{\sqrt{x}-1}+\sqrt{x}\right)\left(\dfrac{x\sqrt{x}+1}{\sqrt{x}+1}-\sqrt{x}\right)\)
\(A=\left[\dfrac{\left(\sqrt{x}\right)^3-1^3}{\sqrt{x}-1}+\sqrt{x}\right]\left[\dfrac{\left(\sqrt{x}\right)^3+1^3}{\sqrt{x}+1}-\sqrt{x}\right]\)
\(A=\left[\dfrac{\left(\sqrt{x}-1\right)\left(x+\sqrt{x}+1\right)}{\sqrt{x}-1}+\sqrt{x}\right]\left[\dfrac{\left(\sqrt{x}+1\right)\left(x-\sqrt{x}+1\right)}{\sqrt{x}+1}-\sqrt{x}\right]\)
\(A=\left(x+\sqrt{x}+1+\sqrt{x}\right)\left(x-\sqrt{x}+1-\sqrt{x}\right)\)
\(A=\left(x+2\sqrt{x}+1\right)\left(x-2\sqrt{x}+1\right)\)
\(A=\left(\sqrt{x}+1\right)^2\left(\sqrt{x}-1\right)^2\)
\(A=\left[\left(\sqrt{x}+1\right)\left(\sqrt{x}-1\right)\right]^2\)
\(A=\left(x-1\right)^2\)
\(A=x^2+2x+1\)
Rút gọn biểu thức :
A =x^2*(a-b) + b*(1-x)+x*(b*x+x) -a*x*(x+1)
B =x^2*(11*x-2)+ b*(x-1)-3*x*(4*x^2-x-2)
D = 2*x^2 +3*(x-1)*(x+1) -5*x*(x-1)
Tìm x biết
a,(1/x2-x+1)-x=1
b,(1/x(x+1))+(1/(x+1)(x+2))+(1/(x+2)(x+3))+(1/x+3)=1/5
Ta có
\(\frac{1}{x^2-x+1}-x=1\)
<=>\(\frac{1-x^3+x^2-x}{x^2-x+1}=1\)
<=>\(1-x^3+x^2-x=x^2-x+1\)
<=>\(x^3=0\)
<=>\(x=0\)
Nhớ tick mình nha bạn,cảm ơn nhiều.
P=(x^2-1/x^4-x^2+1 + 2/x^6+1 - 1/x^2+1).(x^2 - x^4+x^2-1/x^4+x^2+1 )
a,Rút gọn b,Tìm GTLN
Bạn vào biểu tượng \(\Sigma\) để nhập biểu thức cho chính xác nhé
Rút gọn biểu thức sau:
a)x(x-1)(x+1)-(x+1)(x^2-x+1)
b)3x^2(x+1)(x-1)-(x^2-1)(x^4+x^2+1)+(x^2-1)^3
a.\(x\left(x-1\right)\left(x+1\right)-\left(x+1\right)\left(x^2-x+1\right)\)
\(=x\left(x^2-1\right)-\left(x^3+1\right)\)
\(=x^3-x-x^3-1\)
\(=-x-1\)
b.\(3x^2\left(x+1\right)\left(x-1\right)-\left(x^2-1\right)\left(x^4+x^2+1\right)+\left(x^2-1\right)^3\)
\(=3x^2\left(x^2-1\right)-\left(x^2-1\right)^3+\left(x^2-1\right)^3\)
\(=3x^2\left(x^2-1\right)+\left(x^2-1\right)^3\)
Chắc là vậy!
a) \(x\left(x-1\right)\left(x+1\right)-\left(x+1\right)\left(x^2-x+1\right)\)
\(=x.\left(x^2-1^2\right)-\left(x^3+1^3\right)\)
\(=x^3-1x-x^3+1^3\)
\(=-x+1\)
Tìm các số a, b, c biết:
Câu 1: a.(x+1).(x+2)+bx.(x+2)+cx.(x+1)=1
Câu 2: (ax+b).(x-1)+c.(x2+1)=1
Câu 3: a.(x+1).(x+2)+b(x+2)+c(x+1)2=1
1. Thu gọn:
a) 5x. (x-3) - x. (5x+1)
b) -3x. (x-1) - x. (x+1) + 4x. (x-2)
c) (3x-1). (x-2) + (x-1). (x+1)
d) (4x-3). (2x-5) - (8x-2). (x-1)
2. Tìm x:
a) 3x. (x-3) - x. (3x-2) = 2
b) -2x. (x+1) - 3. (1-x) + 2x2
c) (x-2). (x+2) + (3.x). (x+1) = 0
d) (2x-1). (x+3)- (x-2). (2x+1) = 10
1. Thu gọn:
a) 5x. (x-3) - x. (5x+1)
= 5x2 - 15x - 5x2 - x = -16x
b) -3x. (x-1) - x. (x+1) + 4x. (x-2)
= -3x2 + 3x - x2 - x + 4x2 - 8x
= -6x