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AS Mathematics - Core 1 - Indices Problems

  1. Oct 30, 2011 #1
    I am struggling with my mathematics indices homework. I think I have some correct answers so far but I'm pretty stumpted on some others. How would I go about solving the following equations.

    1. The problem statement, all variables and given/known data
    1) 25 to the [itex]\frac{1}{2}[/itex] - [itex]\frac{5 to the -4}{5 to the -5}[/itex]


    2. Relevant equations



    3. The attempt at a solution
    1) 25 to the [itex]\frac{1}{2}[/itex] = [itex]\sqrt{25}[/itex] = 5 i know that
    i get lost on the next bit... i end up with
    [itex]\frac{-625}{-3215}[/itex] and therefor
    5 - [itex]\frac{1}{5}[/itex] = 4[itex]\frac{4}5{}[/itex] but this is not in index form?? if i take it further...
    [itex]\sqrt[5]{4}[/itex] to the 4 and from there i have no idea how to go further, plus i am positive i've gone wrong at a much earlier stage.
     
  2. jcsd
  3. Oct 30, 2011 #2

    Mark44

    Staff: Mentor

    Edited to make readable.
     
  4. Oct 30, 2011 #3

    Mark44

    Staff: Mentor

    Use the fact that a-n = 1/an.

    Also, at this stage in mathematics, we pretty much never write things like 4 [itex]\frac{4}{5}[/itex]. It looks too much like 4 * 4/5. Instead of mixed numbers like this, improper fractions such as 24/5 are preferred.
     
  5. Oct 30, 2011 #4
    thanks for the assistance its a bit late for me to crack on with the problem at the moment I will return tomorrow and have another go.

    Could you please tell me how you put the 1/2 index power or direct me to a link where I can learn how to do this... is it simply html code like the ones provided on your symbol toolbar?
     
  6. Oct 30, 2011 #5

    Mark44

    Staff: Mentor

    You can write exponents, as we in the US call them, by clicking Go Advanced, which opens another menu. Use the X2 button to make exponents.
     
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