Hi all, This question appeared in a logarithm chapter. (√(4+√15))^x + (√(4-√15))^x = 8 i simply can't crack it... thanks, Raz.
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Originally Posted by razidan Hi all, This question appeared in a logarithm chapter. (√(4+√15))^x + (√(4-√15))^x = 8 By inspection $\displaystyle x=2$.
Can I see the full solution please?
Originally Posted by razidan Can I see the full solution please? So far as I know, there is no simple solution other than by inspection. I also think that is the whole point of this question. I have seen hundreds like it.
Really? I would guess they want me to somehow translate it into a logarithmic equation, that's the whole purpose of that chapter...
Originally Posted by razidan Really? I would guess they want me to somehow translate it into a logarithmic equation, that's the whole purpose of that chapter... Well did you post it correctly? Is it product and not a sum?
number 4.30
Originally Posted by razidan number 4.30 I see you posted correctly. Then it is just a poorly constructed problem if you are expect to use any method other than inspection. It is no different from solving $\displaystyle 16^x+9^x=25.$ There is no elementary algebraic solution.
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