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Math Help - exponential function

  1. #1
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    exponential function

    A city is growing at the rate of 0.5% annually. If there were 3,896,000 residents in the city in 1995, find how many (to the nearest ten-thousand) are living in that city in 2000. Use the equation f(t)=3,896,000(2.7)^0.005t
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    Quote Originally Posted by getnaphd View Post
    A city is growing at the rate of 0.5% annually. If there were 3,896,000 residents in the city in 1995, find how many (to the nearest ten-thousand) are living in that city in 2000. Use the equation f(t)=3,896,000(2.7)^0.005t
    plug in t = 5 and solve
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  3. #3
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    I tried that but I still did not come up with the correct answer.

    This is what I did:
    f(t)=3,896,000(2.7)^0.005(5)

    Is this right?
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  4. #4
    is up to his old tricks again! Jhevon's Avatar
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    Quote Originally Posted by getnaphd View Post
    I tried that but I still did not come up with the correct answer.

    This is what I did:
    f(t)=3,896,000(2.7)^0.005(5)

    Is this right?
    yes (but technically you should have f(5) on the left)

    but yes, the value of that function is the answer. remember 0.005(5) is a power. be careful how you input this into your calculator

    if you don't have a calculator with a secondary display, like a TI-89 or whatever, you have to input 2.7^[0.005(5)] first, and then multiply that answer by 3896000
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  5. #5
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    The answer is 3,990,000 but I still do not understand how this came about. I did everything like you said and I still did not come up with this answer.

    I have a TI-83 calculator.

    This is what I input: 389600(2.7)^0.005(5) is this correct?
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    is up to his old tricks again! Jhevon's Avatar
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    Quote Originally Posted by getnaphd View Post
    The answer is 3,990,000 but I still do not understand how this came about. I did everything like you said and I still did not come up with this answer.

    I have a TI-83 calculator.

    This is what I input: 389600(2.7)^0.005(5) is this correct?
    the answer you should get is 3993953.85 then you round that off to 3990000 since the question said to the nearest 10000
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  7. #7
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    I did not multiply the 5 with 0.005 first. With this way I came up with 399395.

    Thank you soooo much. I finally got it after 12 tries.
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