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Mathematics 18 Online
OpenStudy (anonymous):

can anybody please help me with this?

OpenStudy (anonymous):

OpenStudy (anonymous):

Do I first substitute (1-i sqrt of 2) in x?

terenzreignz (terenzreignz):

mhmm

OpenStudy (fifciol):

yes, just subsitute

OpenStudy (anonymous):

and how do I simplify next?

OpenStudy (fifciol):

multiply by conjugate of denominator both , denominator and numerator so that you multiply by one which doesn't change the value of expression but helps you to simplify

OpenStudy (anonymous):

to multiply with \[2 + (1+i \sqrt {2})\]

OpenStudy (anonymous):

?

OpenStudy (fifciol):

first simplify it a little: denominator : 2-(1-isqrt2) = 1+isqr2 its conjugate: 1- isqrt2 but your conjugate could be correct as well

OpenStudy (anonymous):

plug it in and resolve the top. then mult top and bottom by the conjugate of the bottom to get your answer

OpenStudy (fifciol):

what ans you get?

OpenStudy (anonymous):

I am sorry... I am confused!!! :(

OpenStudy (fifciol):

ok , after substitution: \[\frac{ (1-i \sqrt 2)^2 }{ 2-(1-i \sqrt 2) }=\frac{ 1 -2i \sqrt 2 + i^2*2 }{1+i \sqrt 2 }=\frac{ 1-2 i \sqrt 2-2 }{1+i \sqrt 2}\] remember i^2 =-1

OpenStudy (fifciol):

now multiply that by: \[\frac{ 1- i \sqrt 2 }{ 1- i \sqrt 2 }\]

OpenStudy (anonymous):

\[\frac{ 1 -2i \sqrt{2} -2 +1 - i \sqrt {2} }{ 1^{2} - (i \sqrt{2})^{2} }\]

OpenStudy (anonymous):

is this correct?

OpenStudy (fifciol):

denominator is good but numerator is \[(1- 2 i \sqrt 2 -2)(1-i \sqrt 2)= (-1-2 i \sqrt 2)(1-i \sqrt 2)=-(1+2 i \sqrt 2)(1-i \sqrt 2)\]

OpenStudy (anonymous):

thanks!!!

OpenStudy (fifciol):

what is your answer ?

OpenStudy (anonymous):

i still didnt finish :(

OpenStudy (anonymous):

I dont know how to continue!!

OpenStudy (fifciol):

ok \[-(1+2 i \sqrt 2)(1- i \sqrt 2)=-(1-i \sqrt 2 + 2 i \sqrt 2 - i^2*2*\sqrt 2^2)\]

OpenStudy (fifciol):

= \[-5- i \sqrt 2\]

OpenStudy (anonymous):

this is for the numerator

OpenStudy (fifciol):

yes

OpenStudy (anonymous):

and for denominator?

OpenStudy (anonymous):

how do I simplify it

OpenStudy (fifciol):

1- (-2)=3

OpenStudy (anonymous):

thank you so much!!!!!!

OpenStudy (fifciol):

yw

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