====== Question 1, Review Exercise 1 ======
Solutions of Question 1 of Review Exercise 1 of Unit 01: Complex Numbers. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.
===== Question 1 =====
Chose the correct option.
i. ${{\left( \dfrac{2i}{1+i} \right)}^{2}}$
* (a) $i$
* (b) $2i$
* %%(c)%% $1-i$
* (d) $i+1$ \\ See Answer(B): $2i$
ii. Divide $\dfrac{5+2i}{4-3i}$
* (a) $-\dfrac{7}{25}+\dfrac{26}{25}i$
* (b) $\dfrac{5}{4}-\dfrac{2}{3}i$
* %%(c)%% $\dfrac{14}{25}+\dfrac{23}{25}i$
* (d) $\dfrac{26}{7}+\dfrac{23}{7}i$ \\ See Answer(C): $\dfrac{14}{25}+\dfrac{23}{25}i$
iii. ${{i}^{57}}+\frac{1}{{{i}^{25}}}$, when simplified has the value
* (a) $0$
* (b) $2i$
* %%(c)%% $-2i$
* (d) $2$ \\ See Answer(A): $0$
iv. 1+{i}^{2}+{i}^{4}+{i}^{6}+...+{i}^{2n}$ is
* (a) positive
* (b) negative
* %%(c)%% $0$
* (d) cannot be determined \\ See Answer(D): cannot be determined
v. If $z=x+iy$ and $|\dfrac{z-5i}{z+5i}|=1$, then $z$ lies on
* (a) $X-axis$
* (b) $Y-axis$
* %%(c)%% line $y=5$
* (d) None of these \\ See Answer(C): $y=5$
vi. The multiplicative inverse of $z=3-2i$, is
* (a) $\dfrac{1}{3}\left( 3+2i \right)$
* (b) $\dfrac{1}{13}\left( 3+2i \right)$
* %%(c)%% $\dfrac{1}{13}\left( 3-2i \right)$
* (d) $\dfrac{1}{4}\left( 3-2i \right)$ \\ See Answer(B): $\dfrac{1}{13}\left( 3+2i \right)$
vii. If $\left( x+iy \right)\left( 2-3i \right)=4+i$, then
* (a) $x=-\dfrac{14}{13},y=\dfrac{5}{13}$
* (b) $x=\dfrac{5}{13},y=\dfrac{14}{13}$
* %%(c)%% $x=\dfrac{14}{13},y=\dfrac{5}{13}$
* (d) $x=\dfrac{5}{13},y=-\dfrac{14}{13}$ \\ See Answer(B): $x=\dfrac{5}{13},y=\dfrac{14}{13}$
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[[fsc-part1-kpk:sol:unit01:review-ex-1-p2|Question 2 & 3 >]]