Mathematics
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OpenStudy (itiaax):
HELP WITH COMPLEX NUMBERS.
*question attached below*
Will give medal and fan :)
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OpenStudy (itiaax):
Can I have some help on this problem, please?
OpenStudy (mathmath333):
any idea u have?
OpenStudy (itiaax):
None :(
OpenStudy (mathmath333):
first put the values z=x+iy in the fraction (z+i)/(z+2)
OpenStudy (mathmath333):
then arrange the numerator and denomintor in (a+bi) form
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OpenStudy (mathmath333):
for example the denominator comes a+(c+d)i then rationalize the denominator
using a-(c+d)i
OpenStudy (mathmath333):
then rearrange the result in a+bi form
OpenStudy (mathmath333):
as it is given im(z+i)/(z+2)=0,
therefore bi will be zero
OpenStudy (mathmath333):
that is the imaginary part will be zero
OpenStudy (itiaax):
For the first part, I ended up with ](x+i(y+1)/(x+2)+iy] =0
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OpenStudy (mathmath333):
so multiply the numerator and denominator with [(x+2)-iy] to rationalize the denominator
OpenStudy (itiaax):
Give me a sec to work it out :)
OpenStudy (itiaax):
I ended up with: x^2+2x+2iy+y^2+ix+2i+y
OpenStudy (mathmath333):
where is the denominator?
OpenStudy (itiaax):
Oh let me do that one now :$ sorry
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OpenStudy (itiaax):
The denominator is x^2+y^2+4x+4
OpenStudy (mathmath333):
ok now arrange numerator in (a+bi) form
OpenStudy (itiaax):
[(x^2 + y^2 +2x +y) + ((2iy+ix+2i)] ?
OpenStudy (mathmath333):
no , u have to take out 'i' common like a+(c+d)i
and it also seems wrong in calculation
OpenStudy (itiaax):
Wouldn't a be the real part/the real values?
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OpenStudy (mathmath333):
yes it would be
OpenStudy (itiaax):
[(x^2 + y^2 +2x +y) + (i(2y+x+2)]
OpenStudy (mathmath333):
well i came up with x^2+y^2+2x+y+i(x+2y-xy+2)
OpenStudy (mathmath333):
check if u hve done it wrong
OpenStudy (itiaax):
This is what Wolfram Alpha gave me: x^2+i (x+2 y+2)+2 x+y^2+y
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OpenStudy (mathmath333):
ok sry
so now write it with denominator
in the form a+bi
OpenStudy (mathmath333):
as real part dosn't matter here so write only imaginary part=0
OpenStudy (mathmath333):
and note real part too ,it will helpful for 2nd question
OpenStudy (itiaax):
I'm a bit confused :S
OpenStudy (mathmath333):
why
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OpenStudy (itiaax):
I don't understand why the imaginary part =0
OpenStudy (mathmath333):
lol , it is given 0 cuz u will get equation of straight line from that
OpenStudy (itiaax):
Okay. So, we're writing the denominator in the form a+ib now?
OpenStudy (mathmath333):
no denominator doesnt have i ,u have to numerator /denominator and then arrange in (a+bi) form
OpenStudy (itiaax):
So then, we have (x^2+i (x+2 y+2)+2 x+y^2+y)/(x^2+y^2+4x+4)
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OpenStudy (mathmath333):
yes seperate it like( a/b )+(c/d)i
OpenStudy (itiaax):
:S
OpenStudy (itiaax):
How can I do that?
OpenStudy (mathmath333):
lol
(x^2+2 x+y^2+y)/(x^2+y^2+4x+4)+i (x+2 y+2)/(x^2+y^2+4x+4)
OpenStudy (mathmath333):
oops sry it will not equal to 1,lol
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OpenStudy (mathmath333):
just put i (x+2 y+2)/(x^2+y^2+4x+4)=0 and calculate
OpenStudy (mathmath333):
as imagnery part is zero for que 1
OpenStudy (itiaax):
When I paste this into the solver it is giving me an error
OpenStudy (mathmath333):
put in wolfram
OpenStudy (itiaax):
Wolfram gave me the same equation I put in :O
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OpenStudy (mathmath333):
u will get (x+2 y+2=0)
OpenStudy (mathmath333):
see in the solution part
OpenStudy (mathmath333):
thus its a straight line proved.
OpenStudy (mathmath333):
for question 2,
(x^2+2 x+y^2+y)/(x^2+y^2+4x+4)=0
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OpenStudy (mathmath333):
that is (x^2+2 x+y^2+y)=0
OpenStudy (mathmath333):
its the standard equation of circle
OpenStudy (mathmath333):
check its centre and radius
OpenStudy (mathmath333):
it will match with that given in the question
OpenStudy (itiaax):
Yup :)
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OpenStudy (mathmath333):
yo so how u feel now was that easy
OpenStudy (itiaax):
Yup, very :D
OpenStudy (itiaax):
One question, though..did we ignore the Im and the Re?
OpenStudy (mathmath333):
i cant get?
OpenStudy (mathmath333):
what u trying to say
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OpenStudy (itiaax):
Like in the question where it said Im(z+i/Z+2) and Re(z+i/z+2)
OpenStudy (mathmath333):
yes we only work on the data given
OpenStudy (mathmath333):
dont care about anything else
OpenStudy (itiaax):
Alrighty. Thank you sooooo much for your time, help and patience :)
OpenStudy (mathmath333):
\(\Huge\tt \color{black}{\ddot\smile}\)