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How do i approach C number set. How do i think about the real and imaginary part ?
For instance can i solve with this real and imaginary part method this:
z=(2+1)(x-3i)-2i
for which x is z going to be R
I have found the correct anwser by throwing in numbers from 1 to 10, can someone help me find a better way ?
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>>9074035
>z=(2+1)(x-3i)-2i
do you mean z=(2+i)(x-3i)-2i ?
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>>9074035
Write x as a+bi. (a and b are real)
Expand the whole right hand side.
Collect together all terms that do not have i (real part)
Collect together all terms that do have i (imaginary part)
If you require z to be real, set the imaginary part of the R.H.S. equal to 0.
This will give you what constraints a and b should satisfy to make z real.
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Stupid frogposter.
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