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Homework Help: Pythagorean Theorem proof Vector Calc. Due tomorrow 9am. PLEASE HELP

  1. Sep 3, 2008 #1
    Pythagorean Theorem proof Vector Calc. Due tomorrow 9am. PLEASE HELP!!

    Prove the Pythagorean theorem. That is, if a,b, and c are vectors in Rn such that a + b = c and a.b = 0, then ||a||2 + ||b||2 = ||c||2. Why is this called the Pythagorean theorem.

    Hint given: Given the hypotheses, you have a right triangle. Why?

    Help please! This is due tomorrow morning and I cannot figure it out.

    ||x||= length of variable
    a.b= dot product
     
  2. jcsd
  3. Sep 3, 2008 #2
    Re: Pythagorean Theorem proof Vector Calc. Due tomorrow 9am. PLEASE HELP!!

    Well what does [tex] a \cdot b = 0 [/tex] tell you about the vectors a and b?
     
  4. Sep 3, 2008 #3

    rock.freak667

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    Homework Helper

    Re: Pythagorean Theorem proof Vector Calc. Due tomorrow 9am. PLEASE HELP!!

    Draw a triangle,explain why the angle is 90 degrees and then think cosine rule.
     
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