College Algebra (6th Edition)

Published by Pearson
ISBN 10: 0-32178-228-3
ISBN 13: 978-0-32178-228-1

Chapter 1 - Equations and Inequalities - Exercise Set 1.4 - Page 143: 76

Answer

$\dfrac{1+i}{1+2i}+\dfrac{1-i}{1-2i}=\dfrac{6}{5}$

Work Step by Step

$\dfrac{1+i}{1+2i}+\dfrac{1-i}{1-2i}$ Evaluate the sum of fractions: $\dfrac{1+i}{1+2i}+\dfrac{1-i}{1-2i}=\dfrac{(1+i)(1-2i)+(1+2i)(1-i)}{(1+2i)(1-2i)}=...$ $...=\dfrac{1-2i+i-2i^{2}+1-i+2i-2i^{2}}{1^{2}-(2i)^{2}}=\dfrac{2-4i^{2}}{1-4i^{2}}=...$ Substitute $i^{2}$ by $-1$ and simplify: $...=\dfrac{2-4(-1)}{1-4(-1)}=\dfrac{2+4}{1+4}=\dfrac{6}{5}$
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