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Mathematics 20 Online
OpenStudy (anonymous):

http://prntscr.com/40fxbu help me prove this two expression are the same

OpenStudy (anonymous):

So you want to simplify the left side?

OpenStudy (anonymous):

yeah basically the right side is the answer

OpenStudy (anonymous):

please help i kind of stuck

OpenStudy (anonymous):

All you need to know is, \[\huge x ^{-n} = \frac{ 1 }{ x }\]

OpenStudy (anonymous):

i know that let me show you how im doing i just cant seem to get to the answer

OpenStudy (anonymous):

Alright

OpenStudy (anonymous):

\[\huge \frac{ a ^{-1}b ^{-2}+a ^{-2}b ^{-1} }{ b ^{-2}-a ^{-2} }\] I'll write it out here for reference.

OpenStudy (anonymous):

http://prntscr.com/40ghj3

OpenStudy (anonymous):

so thats where im stuck

OpenStudy (anonymous):

ok let me check

OpenStudy (anonymous):

Ok sec, let me do this, just need to put it over a common denominator I guess.

OpenStudy (anonymous):

Guess it will require some work haha, alright I'll do this and you can see my steps alright?

OpenStudy (anonymous):

ok nice, beacause i cant seem to find things to cancel out

OpenStudy (anonymous):

ok thank you.

OpenStudy (anonymous):

\[\huge \frac{ a ^{-1}b ^{-2}+a ^{-2}b ^{-1} }{ b ^{-2}-a ^{-2} } = \frac{ \frac{ 1 }{ ab^2 }+\frac{ 1 }{ a^2b } }{b ^{-2}-a ^{-2} }\] Agree?

OpenStudy (anonymous):

yeah

OpenStudy (anonymous):

Ok now we'll put it over a common denominator \[\huge \frac{ 1 }{ ab^2 }+\frac{ 1 }{ a^2b } = \frac{ a }{ a^2b^2 }+\frac{ b }{ a^2b^2 } \implies \frac{ \frac{ a }{ a^2b^2 }+\frac{ b }{ a^2b^2 } }{ b ^{-2}-a ^{-2} }\]

OpenStudy (anonymous):

oj i cant see part of it

OpenStudy (anonymous):

Yeah sorry, I lost connection OS, you know how it is >_>

OpenStudy (anonymous):

hehe

OpenStudy (anonymous):

\[\huge \frac{ \frac{ a }{ a^2b^2 }+\frac{ b }{ a^2b^2 } }{ b ^{-2}-a ^{-2} }\] \[\huge = \frac{ \frac{ a+b }{ a^2+b^2 } }{ b ^{-2}-a ^{-2} }\] \[\huge = \frac{ a+b }{ a^2b^2\frac{ a^2 }{ a^2b^2 }-\frac{ b^2 }{ a^2b^2 } }\] put b^-2-a^-2 over the common denominator \[\huge = \frac{ a+b }{ a^2b^2\frac{ a^2-b^2 }{ a^2b^2 } } \] \[\huge = \frac{ a+b }{ a^2b^2 \frac{ (a-b)(a+b) }{ a^2b^2 } }\] Using difference of squares \[\huge = \frac{ a^2b^2(a+b) }{ a^2b^2(a-b)(a+b) } \implies \frac{ 1 }{ a-b }\] cancelling common terms.

OpenStudy (anonymous):

whoa let me digest that please.

OpenStudy (anonymous):

Take your time ^.^

OpenStudy (anonymous):

my friend did you sum again the fraction right to obtein a+b / a^2+b^2 right?

OpenStudy (anonymous):

http://prntscr.com/40goxu could you explain me the procedure to get that

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