Can someone help me with this one?
Find the real and complex solution of the equation x[squared]-8=0.
Possible answers:
1. -2, 2, 2cis(pi/3)
2. 2, 2cis(2pi/3), 2cis(4pi/3)
3. -2, 2cis(pi/3), 2cis(2pi/3)
4. 2cis(pi/3), 2cis(2pi/3), 2cis(4pi/3)
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Can someone help me with this one?
Find the real and complex solution of the equation x[squared]-8=0.
Possible answers:
1. -2, 2, 2cis(pi/3)
2. 2, 2cis(2pi/3), 2cis(4pi/3)
3. -2, 2cis(pi/3), 2cis(2pi/3)
4. 2cis(pi/3), 2cis(2pi/3), 2cis(4pi/3)
Are you sure that you have typed the question correctly. the only solutionsQuote:
Originally Posted by mike1
of $\displaystyle x^2-8=0$, are $\displaystyle x=\pm \sqrt{8}$.
From the list of solutions I would guess you are asked for the solutions of:
$\displaystyle x^3-8=0$,
in which case the answer will be 2, which you can check by cubing each of
the solutions in the lis to check that they come to 8.
RonL
If x[squared] -8 = 0Quote:
Originally Posted by mike1
is x^2 -8 = 0
then,
(x+sqrt(8))(x-sqrt(8)) = 0
x = +,-sqrt(8)
x = +,-2sqrt(2) ------------answer.
Another way,
x^2 -8 = 0
x^2 = 8
x = +,-sqrt(8)
.....
The answers are not in the multiple choice.
The answers are all real numbers. No complex.
Now I'm really confused. Do you really think my worksheet is wrong?
Quote:
Originally Posted by mike1
The equation given to solve is a quadratic, the solution sets contain
three solutions, which is a charateristic in the complex domain of the
roots of a cubic.
So yes there is a mistake somewhere.
RonL
