Square root of a complex number!

Does anyone knows how to get the square root of a complex number?

For example if i want the square root of (23+40i), the Casio FX115 ES and MS gives me a math error. If i use the TI-92plus which is not allowed for the exam gives me the correct answer without problems.

Any ideas?

Convert it to polar. Take the square root of the magnitude. Divide the angle in half. Convert back to rectangular.

I get 5.88+j3.40.

Wildsoldier said:

Does anyone knows how to get the square root of a complex number?
For example if i want the square root of (23+40i), the Casio FX115 ES and MS gives me a math error. If i use the TI-92plus which is not allowed for the exam gives me the correct answer without problems.

Any ideas?

Click to expand...

I get 4.197501899 using a Casio fx-115ES. I did shift - 2 3 shift ) 4 0 ) = sqrt Ans

Compare my answer to what you got on the TI-92, was it the same?

It must be wrong since I lost the imaginary number somewhere.

Looks like Flyer has the right method.

Thanks i'm going to check when i get back home. I'm at work right now and i dont have the TI here to check. That number that i put was an example!

EEVA said:

Wildsoldier said:

Does anyone knows how to get the square root of a complex number?
For example if i want the square root of (23+40i), the Casio FX115 ES and MS gives me a math error. If i use the TI-92plus which is not allowed for the exam gives me the correct answer without problems.

Any ideas?

Click to expand...

I get 4.197501899 using a Casio fx-115ES. I did shift - 2 3 shift ) 4 0 ) = sqrt Ans

Compare my answer to what you got on the TI-92, was it the same?

It must be wrong since I lost the imaginary number somewhere.

Looks like Flyer has the right method.

Click to expand...

Flyer_PE said:

Convert it to polar. Take the square root of the magnitude. Divide the angle in half. Convert back to rectangular.
I get 5.88+j3.40.

Click to expand...

this is correct. I followed Flyer's directions on my Casio fx-115ES and double checked it with my HP48G and get the same answer, 5.88 + j3.40.

arty-smiley-048:

petobe-gw said:

Flyer_PE said:

Convert it to polar. Take the square root of the magnitude. Divide the angle in half. Convert back to rectangular.
I get 5.88+j3.40.

Click to expand...

this is correct. I followed Flyer's directions on my Casio fx-115ES and double checked it with my HP48G and get the same answer, 5.88 + j3.40.

arty-smiley-048:

Click to expand...

Yup is correct i checked at home at gives the right answer. Thanks Flyer PE

Wildsoldier said:

Does anyone knows how to get the square root of a complex number?
For example if i want the square root of (23+40i), the Casio FX115 ES and MS gives me a math error. If i use the TI-92plus which is not allowed for the exam gives me the correct answer without problems.

Any ideas?

Click to expand...

Wildsoldeir : Just apply "de Moivre theorem" , look at your Math book (Trig) , here is the link in wikipedia ,

http://en.wikipedia.org/wiki/De_Moivre%27s_formula

Jonjo