Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Help with Algebra 2/Trigonometry problem

  1. Oct 23, 2003 #1
    I'm having trouble with proving this equation: x=-b\2a
    I am not really familiar with this equation but my trigonometry teacher says it is something from Algebra 2. How can I prove why or how this equation works for finding the x-coordinate?
     
  2. jcsd
  3. Oct 24, 2003 #2

    HallsofIvy

    User Avatar
    Staff Emeritus
    Science Advisor

    What do you mean "prove it"? It's an equation- its sometimes true and sometimes not. I suppose you mean "prove it is true for this particular situation" but you haven't told us what the situation is.
    Could you please state the entire problem exactly?
     
  4. Oct 24, 2003 #3
    Using simple calculus, you can show that x=-b/2a is the point at which a parabola attains a minimum or maximum.
    The vertical line x=-b/2a that goes thru this point is the axis of symmetry.
     
  5. Oct 24, 2003 #4

    HallsofIvy

    User Avatar
    Staff Emeritus
    Science Advisor

    Ah! Thanks, Stephen, I recognized "-b/(2a)" as part of the quadratic formula but didn't recognize that he was asking for a proof that the x coordinate of the vertex of the parabola y= ax2+ bx+ c is -b/(2a).
     
  6. Oct 28, 2003 #5
    wait isn't -b/2a the vertex of a parabola? i kinda of forgot this but i think you can the coeficients of b and a get the vertex of the parabola
     
  7. Oct 28, 2003 #6

    HallsofIvy

    User Avatar
    Staff Emeritus
    Science Advisor

    Yes, that was what StephenPrivitera told you!
     
  8. Oct 28, 2003 #7
    o sorry i only saw the oroginal question
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Help with Algebra 2/Trigonometry problem
  1. Trigonometry help (Replies: 7)

  2. Trigonometry Help (Replies: 7)

Loading...