====== 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): $x=\dfrac{5}{13},y=\dfrac{14}{13}$ ====Go To==== [[fsc-part1-kpk:sol:unit01:review-ex-1-p2|Question 2 & 3 >]]