Alan

I suspect this should be:

"The function D(t) can be used to approximate the total average credit card debt in a U.S. household (in thousands of dollars) t years after 1995. 

Interpret the meaning of the statement: D(30)=18.9"

D(30) = 18.9 then means that the average credit card debt in a US household in the year 2025 (i.e. 1995 + 30) will be $18900.

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There are no real solutions!!

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"Hi I am trying to figure out how to caculate a cosine graph for the following data points:  ..."

The following might be of some use.  The results were obtained using a non-linear fitting routine (part of a technical software package) - not the sort of thing you want to do by hand!:

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When x>1 f(x) = g(x) and both are real

When -1 < x < 1 both f(x) and g(x) are imaginary

When x< -1 f(x) is real but g(x) is imaginary

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Need to be careful here heureka

\(\sqrt{-2}\rightarrow i\sqrt2\\ \sqrt{-12}\rightarrow 2i\sqrt3\)

Multiply these together and you should get a negative result.

Pi cannot be expressed as a fraction (I.e. as the ratio of two integers). 3.14 is an approximation to pi.

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The lowest 5% of a normal distribution is about 1.645 standard deviations below the mean. So if her city's average price is less than 2.79 - 1.645*0.14 = 2.56 then it is significantly lower than the national average at the 0.05 significance level. If it is not lower than this then it is not significantly lower at the 0.05 level.  

To find the average of her city's gas price, add up the twelve prices given and divide by 12.

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True, but it's a better likeness of pi than ♦ !!!

The pi thing!

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Hi Melody,

The other sections haven't worked properly for a long time.  I check from time to time.

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