Mathematics
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OpenStudy (anonymous):
complex numbers: find a, b such that (-bi)^2 = a^2 ?
14 years ago
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OpenStudy (anonymous):
a^2+b^2=0;
a=m+ni
b=p+qi
(m+ni)^2+(p+qi)^2=0
m^2+p^2=n^2+q^2....(1)
mn=pq;....(2)
now choose m,n,p,q such that the conditions 1,2 satisfied simultaneously....
14 years ago
OpenStudy (anonymous):
are a and b complex numbers ?
14 years ago
OpenStudy (anonymous):
yes...
its given..
14 years ago
OpenStudy (anonymous):
how did you get mn = pq
14 years ago
OpenStudy (anonymous):
sorry that will be mn=-pq.
14 years ago
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OpenStudy (anonymous):
also you foiled wrong
14 years ago
OpenStudy (anonymous):
(m+ni)^2+(p+qi)^2 = m^2 + 2mni -n^2 + p^2 + 2pqi - q^2 = 0
14 years ago
OpenStudy (anonymous):
so???
14 years ago
OpenStudy (anonymous):
where is 2mni and 2pqi
14 years ago
OpenStudy (anonymous):
2mn=2pq
=> mn=pq
14 years ago
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OpenStudy (anonymous):
in your algebra , i dont see it
14 years ago
OpenStudy (anonymous):
i have done it in single step.
14 years ago
OpenStudy (anonymous):
too fast for me
14 years ago
OpenStudy (anonymous):
sorry im doing another problem, helping student, one sec
14 years ago
OpenStudy (anonymous):
i dont follow your logic
14 years ago
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OpenStudy (anonymous):
oh
14 years ago
OpenStudy (anonymous):
2mn i = -2pqi
14 years ago
OpenStudy (anonymous):
ok then mn = -pq, agreed
14 years ago
OpenStudy (anonymous):
something tells me that a,b are integers though originally
14 years ago
OpenStudy (anonymous):
btw: a and b are real
14 years ago
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OpenStudy (anonymous):
the correct answer is: a=b?
14 years ago
OpenStudy (anonymous):
our guy here thinks that a and b are complex numbers , i thought this was simpler, lol
14 years ago
OpenStudy (anonymous):
the question is: find a and b (both real) such that (-bi)^2 = a^2
14 years ago
OpenStudy (anonymous):
if a, b are not complex then the relation (a)^2=(-bi)^2 does not hold.
14 years ago
OpenStudy (anonymous):
so a=b=0
14 years ago
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OpenStudy (anonymous):
right
14 years ago
OpenStudy (anonymous):
see your question starts with "complex numbers". so i thought that
14 years ago
OpenStudy (anonymous):
sorry
14 years ago
OpenStudy (anonymous):
this equation only have a trivial solution..
14 years ago
OpenStudy (anonymous):
yeah, no fun
14 years ago
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OpenStudy (anonymous):
why a = b = 0? is it because a^2 + b^2 = 0 + 0i?
14 years ago
OpenStudy (anonymous):
so the question is more interesting if you allow a and b to be complex , right?
14 years ago
OpenStudy (anonymous):
for real no. only a=b=0 holds
14 years ago
OpenStudy (anonymous):
ok
14 years ago
OpenStudy (anonymous):
a^2 = (-b*i)^2 = b^2*i^2 = b^2 *-1 ,
14 years ago
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OpenStudy (anonymous):
can you find any such a,b other than 0 that holds your condition????????????????
14 years ago
OpenStudy (anonymous):
so a^2 = -b^2 , so a^2 + b^2 = 0,
14 years ago
OpenStudy (anonymous):
no because a^2>=0 , and b^2 >= 0
14 years ago
OpenStudy (anonymous):
see i think a,b must be considered as complex otherwise its very easy....
14 years ago
OpenStudy (anonymous):
just solve the damn equation, lol
14 years ago
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OpenStudy (anonymous):
if you take them complex then also you will find a solution 0+0i along with some new solution...
14 years ago
OpenStudy (anonymous):
ahhh
14 years ago
OpenStudy (anonymous):
so this equation is equilvalent, find all a,b, such that a^2 + b^2 = 0, for a,b element of C
14 years ago
OpenStudy (anonymous):
damn...i have another typo: -(bi)^2 = a^2...therefore b^2 = a^2 - so the solution is a = b?
14 years ago
OpenStudy (anonymous):
right?
14 years ago
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OpenStudy (anonymous):
noooooooooooooooooooooooooooooooooo
14 years ago
OpenStudy (anonymous):
(-bi)^2 does not mean -(bi)^2
14 years ago
OpenStudy (anonymous):
yes i know
14 years ago
OpenStudy (anonymous):
find a and b (both real) such that -(bi)^2 = a^2.......this is the correct problem statement.....sorry....
14 years ago