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Mathematics 7 Online
OpenStudy (anonymous):

i^-13

OpenStudy (lgbasallote):

hint: \[\large i^1 = i\] \[\large i^2 = -1\] \[\large i^3 = i^2 \times i - -1 \times i = -i\] \[\large i^4 = (i^2)^2 = (-1)^2 = 1\] \[\large i^5 = i\] so the process repeats does that help?

OpenStudy (anonymous):

it is raised to a negative number though. how does that work?

OpenStudy (lgbasallote):

simple..change it first to \[\huge \frac{1}{i^{13}}\]

OpenStudy (anonymous):

I was told to always go with the i^4 so what I have so far is: 1/(i^4)^3i=1/i

OpenStudy (lgbasallote):

that's right

OpenStudy (anonymous):

so then how is the answer -i, is it the reciprocal?

OpenStudy (lgbasallote):

maybe you mean \[i^{-1}?\]

OpenStudy (anonymous):

oh no I'm confused now. LOL. how did you get i^-1

OpenStudy (lgbasallote):

\[i^{-1} = \frac 1i\]

OpenStudy (anonymous):

then how is the answer expected to be -i? I have the answer sheets for my review, I just don't know how she got to -i, when I keep getting 1/i

OpenStudy (lgbasallote):

are you sure the question is \[\huge i^{-13}\] maybe it's \[\huge -i^{13}\]

OpenStudy (lgbasallote):

\[\huge i^{-13} = \frac 1i\] \[\huge -i^{13} = -i\]

OpenStudy (lgbasallote):

uhmm wait...

OpenStudy (anonymous):

I'm waiting. lol.

OpenStudy (lgbasallote):

OHHH i see

OpenStudy (lgbasallote):

\[\huge \frac 1i \implies \frac 1i \times \frac ii \implies \frac{i}{i^2}\implies \frac{i}{-1} \implies -i\] it's rationalization

OpenStudy (lgbasallote):

how could i forget =))

OpenStudy (lgbasallote):

did you get what i did?

OpenStudy (anonymous):

BRILLIANT!!!!!! Thanks a million.

OpenStudy (lgbasallote):

welcome ^_^ just remember to do that everytime there's an i in the denominator

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