Thread: square root of a complex number

Can someone tell me why my calculator is returning a maths error when I try to find the square root of a complex number and how I do it?

Have you entered the right mode (I think on the ti-83 it was: 'a+bi', in stead of 'real')?
Can you give this complex number.

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yeah its in complex mode and the number is 0.1858 + 0.9802i divide by 4.5239x10^-6i

Did you use for the - sign in the exponent the: operation - (from the difference), or the sign - (to indicate a negative number)? Because that's often a problem. Now, you have to take the 'sign' -.

Do you have to take the square root or just divide the two complex numbers?

yeah as in 0.0000045239i. Not sure what the problem is, in the book I've got it shows the equation as Z = the square root of z/y were z and y are complex or polar numbers. It doesnt show anything else.

Most calculators only have very limited support for complex numbers. For instance the graphical one on my desk right now cannot even perform exponentiation of complex numbers at all, and hence cannot calculate the square root of a complex number.
Also, did you put brackets when evaluating 4.5239x10^-6i? If you didn't it's quite possible the calculator understood 4.5239x10^(-6i), not 4.5239x10^(-6) i, and your calculator most likely cannot evaluate complex exponentiation hence math error.

you still haven't stated what calculator you are using.

my TI-84 does this operation fine in classic mode ... will not do it using the "pretty print" mode.

the entire output (not shown in the screen shot) is

467.5473811-43.92149245i

yeah sorry Skeeter its a Casio fx-991ES PLUS

Originally Posted by hunterage2000

yeah sorry Skeeter its a Casio fx-991ES PLUS

Sorry, but I'm not familiar with the operations of Casio calculators. I recommend you try a web search and/or wait for someone here w/ Casio knowledge that maybe can help.

Wolfram alpha or mathematica can also be used for such operations.