Ti-89 calculator help?

Hi guys, I have a problem with a math problem involving my ti-89, hope you can help!

The problem needs to find the coordinates of the minimum of f(x) = |((x + cosx)^1/2)^2| (it's the square root then squared)

This seems straightforward enough, I first tried just graphing the original equation and using the f3-findminimum function. Unfortunately, this gave me an answer way off (I have the answer key).

Then, I squared the square root function to get f(x) = |x + cosx| and did the same thing. This time, I got the right answer the first time, but upon repeat uses of f3 minimum function my x-coordinate remains correct, but my y-coordinate keeps changing and I can't get the right answer anymore!

Can anyone please help me understand what I'm doing wrong, and how to fix it? Easy 10 points for you math people out there!

1 Answer

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  • Anonymous
    8 years ago
    Best Answer

    1) Graph f(x)

    2) F2 > Zoomfit

    3) F5 > Minimum

    4) Get x-coordinate of minimum

    5) Home

    6) Plug in x-coordinate (-0.739085) into x for f(x)

    7) Push button: Diamond > ENTER

    8) Get answer

    Source(s): TI-89 Calculator
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