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Homework Help: Show equality

  1. Aug 26, 2010 #1
    If f(x)= 5^x, show that

    f(x+h) - f(x) / h = (5^x)(((5^h)-1) / h)

    I need a step by step solution or some hints
  2. jcsd
  3. Aug 26, 2010 #2
    Do you know any properties of the exponential function?
  4. Aug 26, 2010 #3
    like the law of exponents? i know most of them. ill apply the laws more thoroughly
    Last edited: Aug 26, 2010
  5. Aug 26, 2010 #4
    Do you think the term "exponential function" has anything to do with the problem you have posed?
  6. Aug 26, 2010 #5
    yes, when i see something like 5^x
  7. Aug 26, 2010 #6
    So, can you state some of the properties of the exponential function?
  8. Aug 26, 2010 #7
  9. Aug 26, 2010 #8
    Ok, so, if [itex]f(x) = 5^{x}[/itex], which one of those would you use (and in what direction, i.e. from left to right or right to left) to express [itex]f(x + h)[/itex]?
  10. Aug 26, 2010 #9
    not sure which one would work for that since i only understand the first 4-5 properties atm but if i have to do something id go with f(x+h) = 5^x + 5^h and that doesn't seem to make a whole lot of sense
  11. Aug 26, 2010 #10
    f(x + h) = 5^{x + h}

    not [itex]5^{x} + 5^{h}[/itex].

    If you are not comfortable with this, I think you need to brush on your pre-calc syllabus.
  12. Aug 26, 2010 #11
    okay i see how it works out now. didn't take calc after high school pre-calc and it's been 3 years, everything is in bit's and pieces..I'm currently brushing my *** off :( thanks for the help Dick
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