Math Problem Statement

show me algebraic proofs

Solution

Here are some common algebraic proofs across various topics, presented step-by-step:


1. Proof: The Difference of Squares Formula

Claim: a2b2=(ab)(a+b)a^2 - b^2 = (a - b)(a + b)

Proof:

  1. Start with the right-hand side: (ab)(a+b)(a - b)(a + b)
  2. Expand using the distributive property: aa+abbabba \cdot a + a \cdot b - b \cdot a - b \cdot b
  3. Simplify the terms: a2+ababb2a^2 + ab - ab - b^2
  4. Combine like terms: a2b2a^2 - b^2
  5. Thus, a2b2=(ab)(a+b)a^2 - b^2 = (a - b)(a + b).

2. Proof: Sum of First nn Integers

Claim: The sum of the first nn integers is given by S=n(n+1)2S = \frac{n(n+1)}{2}.

Proof:

  1. Write the sum forward and backward: S=1+2+3++nS = 1 + 2 + 3 + \ldots + n S=n+(n1)+(n2)++1S = n + (n-1) + (n-2) + \ldots + 1
  2. Add the two equations term by term: 2S=(1+n)+(2+(n1))++(n+1)2S = (1 + n) + (2 + (n-1)) + \ldots + (n + 1)
  3. Note that each pair sums to n+1n+1, and there are nn terms: 2S=n(n+1)2S = n(n+1)
  4. Divide by 2: S=n(n+1)2S = \frac{n(n+1)}{2}

3. Proof: (x+y)2=x2+2xy+y2(x + y)^2 = x^2 + 2xy + y^2

Claim: The square of a binomial expands as given.

Proof:

  1. Start with (x+y)2(x + y)^2: (x+y)(x+y)(x + y)(x + y)
  2. Apply the distributive property: xx+xy+yx+yyx \cdot x + x \cdot y + y \cdot x + y \cdot y
  3. Simplify: x2+xy+xy+y2x^2 + xy + xy + y^2
  4. Combine like terms: x2+2xy+y2x^2 + 2xy + y^2

4. Proof: Transitive Property

Claim: If a=ba = b and b=cb = c, then a=ca = c.

Proof:

  1. Start with the first statement: a=ba = b
  2. Substitute b=cb = c from the second statement into the first: a=ca = c
  3. This proves the transitive property.

5. Proof: x0=1x^0 = 1 (for x0x \neq 0)

Claim: Any non-zero number raised to the power 0 equals 1.

Proof:

  1. Start with the property of exponents: xmxn=xm+nx^m \cdot x^n = x^{m+n}
  2. Set m=0m = 0 and n=kn = k: x0xk=x0+kx^0 \cdot x^k = x^{0+k}
  3. Simplify: x0xk=xkx^0 \cdot x^k = x^k
  4. Divide both sides by xkx^k (valid because x0x \neq 0): x0=1x^0 = 1

Do you have any specific type of proof in mind or would you like detailed steps for one of the above?


Relative Questions:

  1. Can you demonstrate the proof for the quadratic formula derivation?
  2. How can you prove the sum of a geometric series?
  3. Can you prove the (xy)2=x22xy+y2(x-y)^2 = x^2 - 2xy + y^2 identity?
  4. How would you algebraically prove a2=a\sqrt{a^2} = |a|?
  5. What is the proof for the arithmetic mean-geometric mean inequality?

Tip: Always start with what is given (assumptions or known equations) and manipulate step-by-step towards what needs to be proved.

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Math Problem Analysis

Mathematical Concepts

Algebra
Binomial Expansion
Properties of Exponents
Summation
Transitive Property

Formulas

Difference of Squares Formula: a^2 - b^2 = (a - b)(a + b)
Sum of First n Integers: S = n(n+1)/2
Binomial Expansion: (x + y)^2 = x^2 + 2xy + y^2
Properties of Exponents: x^0 = 1

Theorems

Transitive Property of Equality

Suitable Grade Level

Grades 9-12