Dear Physics Forums

  • Thread starter 2Xist
  • Start date
11
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Main Question or Discussion Point

Dear PF,

Your last help to my tech support was very helpful and i thank you all for it :). however since i am new to my TI-Titanum, i unfortunalty have another stupid question. i was using the "slove(" function. and i inserted into the home screen (exactly what i typed in):

solve((-1/2)^x=1/4,X)

i mean.... the answer should be 2 right?
somehow i got a "false" answer
i was just wondering if it is my calculators problem or if if everyones calcucators.
Please try on your own calculators and post results

thank you and please reply asap :)
 

Answers and Replies

267
2
Perhaps you should try == rather = and see what you get.
 
alphysicist
Homework Helper
2,238
1
Hi 2Xist,

Dear PF,

Your last help to my tech support was very helpful and i thank you all for it :). however since i am new to my TI-Titanum, i unfortunalty have another stupid question. i was using the "slove(" function. and i inserted into the home screen (exactly what i typed in):

solve((-1/2)^x=1/4,X)

i mean.... the answer should be 2 right?
somehow i got a "false" answer
i was just wondering if it is my calculators problem or if if everyones calcucators.
Please try on your own calculators and post results

thank you and please reply asap :)
I believe solve() restricts its algorithm to be over real numbers; while it is trying to solve your equation for x it runs into a complex expression.

If you use csolve() you will get a sequence of complex answers (as a complicated expression) one of which is the value 2; you can find the real answer you're looking for by forcing the imaginary part of the sequence to be zero. I don't think that's very practical if all you want is the real solution, but it does work.

You can eliminate the negative sign by hand (putting a contraint on x) and the use solve(). (But I hope you're solving all the problems by hand and only trying to check your work using solve().)
 

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