Complex number as a divisor in synthetic division

$\begingroup$

For the following exercises, use synthetic division to determine the quotient involving a complex number.

Problem π‘₯ + 1 / π‘₯ + 𝑖

Answer 1 + 1 βˆ’ 𝑖 / π‘₯ + 𝑖

I get the correct answer when I do it via long division but I don't get the same answer for synthetic.

$\endgroup$ 1

2 Answers

$\begingroup$

Long division:$$\require{enclose} \begin{array}{rll} 1 \phantom{000}\\[-3pt] x+i \enclose{longdiv}{\quad x+1\phantom{000}}\kern-.2ex \\[-3pt] \underline{x+i\phantom{000}} \\[-3pt] 1-i \\[-3pt] \end{array}$$Synthetic division:$$\require{enclose} \begin{array}{rll} -i\;\; \enclose{longdiv}{\quad1\qquad1\phantom{000}}\kern-.2ex \\[-3pt] \underline{\phantom{0000}-i\phantom{000}} \\[-3pt] 1\qquad 1-i \\[-3pt] \end{array}$$In both cases you end up with: quotient $\;1\;$ and remainder $\;1-i\;$
Here is a good summary polynomial synthetic division.

$\endgroup$ 2 $\begingroup$

This is what my synthetic division looks like. What does your look like?

$\begin{array}{c|cc} &1&1\\-i&&-i\\\hline&1&1-i\end{array}$

Otherwise, I would say

$\frac {x+1}{x+i} = \frac {(x-i) -i + 1}{x+i} = 1 + \frac {1-i}{x+i}$

$\endgroup$ 1

Your Answer

Sign up or log in

Sign up using Google Sign up using Facebook Sign up using Email and Password

Post as a guest

By clicking β€œPost Your Answer”, you agree to our terms of service, privacy policy and cookie policy

You Might Also Like