# Exponent, to a negative exponent. Stroud problem.

• Apr 27th 2011, 05:38 PM
porous
Exponent, to a negative exponent. Stroud problem.
Hi,

I'm a little confused with a problem (very!) early on in the 5th edition of Stroud's Engineering Mathematics.

F1 (pg. 69), #14c

Write each of the following as a number raised to a power: http://quicklatex.com/cache3/ql_6f64...6557e2e_l3.png

The answer given is: http://quicklatex.com/cache3/ql_35eb...bc4c108_l3.png

Naively, I thought:

http://quicklatex.com/cache3/ql_00e9...8fa729e_l3.png

http://quicklatex.com/cache3/ql_5881...9fa4134_l3.png

Although I guess http://quicklatex.com/cache3/ql_483d...d91a483_l3.png would be appropriate according to the wording of the question.

Clearly I'm missing something fundamental, can someone please point me in the right direction?
• Apr 27th 2011, 05:45 PM
Ackbeet
I would say that, while your notation of

$(-4.-4.-4.-4)^{-4}$ isn't quite kosher, the idea is correct. I would write it as $((-4)(-4)(-4)(-4))^{-4}.$

In any case, your answer is correct. The answer of -4 is clearly wrong.
• Apr 27th 2011, 05:50 PM
porous
Argh, thank you. I guess I should have more confidence in myself :). Thanks for the notation tips too, understood.

Many thanks!
• Apr 27th 2011, 05:53 PM
Ackbeet
You're welcome!