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Powers question

  • 04-10-2012 12:05am
    #1
    Registered Users, Registered Users 2 Posts: 4,056 ✭✭✭


    Right here goes

    4^2=16

    2^4=16


    Can i simplify 256^4 down to 2^?


Comments

  • Registered Users, Registered Users 2 Posts: 707 ✭✭✭jeepers101


    You can do this using logs.

    logb(x)=a is another way of saying b^a=x

    Example:

    log2(16)=4 since 2^4=16

    Now back to your problem. If you work out your problem 256^4 you will get some number, say x. You now need to find the log of x to the base 2, log2(x)

    If you try and enter this into your calculator you might have some trouble due to the fact you cannot change the base.

    Use this formula to get around it:

    03a7c4f8461ee26493b9cf547a82e390.png

    You can omit the 'k' when entering this into the calculator.


  • Registered Users, Registered Users 2 Posts: 5,141 ✭✭✭Yakuza


    As 256 = 2^8. then (2^8)^4 = 2^(8*4) or 2^32.

    Generally, (x^y)^z = x^(y*z).

    Some more info here:http://www.mathsrev.com/rules-of-indices/


  • Registered Users, Registered Users 2 Posts: 5,633 ✭✭✭TheBody


    You could think of the problem as trying to factor out all the 2's:

    [latex]256^4=[2(128)]^4[/latex]
    [latex]=[2(2)(64)]^4[/latex]
    [latex]=[2(2)(2)(32)]^4[/latex]
    [latex]=[2(2)(2)(2)(16)]^4[/latex]
    [latex]=[2(2)(2)(2)(2)(8)]^4[/latex]
    [latex]=[2(2)(2)(2)(2)(2)(4)]^4[/latex]
    [latex]=[2(2)(2)(2)(2)(2)(2)(2)]^4[/latex]
    [latex]=[2^8]^4[/latex]
    [latex]=2^{32}[/latex]


  • Registered Users, Registered Users 2 Posts: 4,056 ✭✭✭Sparks43


    Brilliant thanks

    Doing a Network course and was trying to get combinations for sub netting and ipv4

    So its nice to know that i was right and 2^32 is the same as 256^4 also it won me a few pints from so called experts :D


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