Question : If $\left(z+\frac{1}{z}\right)=4$, then what will be the value of $\frac{1}{2}\left(z^2+\frac{1}{z^2}\right)$?
Option 1: 14
Option 2: 16
Option 3: 7
Option 4: 8
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Correct Answer: 7
Solution : $(z+\frac{1}{z})=4$ Squaring both sides, we get: $(z+\frac{1}{z})^2=4^2$ ⇒ $z^2+\frac{1}{z^2}+2×z×\frac{1}{z}=16$ ⇒ $z^2+\frac{1}{z^2}=16-2$ ⇒ $z^2+\frac{1}{z^2}=14$ Thus, $\frac{1}{2}(z^2+\frac{1}{z^2})$ $=\frac{1}{2}×14 = 7$ Hence, the correct answer is 7.
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Question : If $2 x+\frac{2}{x}=5$, then the value of $\left(x^3+\frac{1}{x^3}+2\right)$ will be:
Option 1: $\frac{81}{11}$
Option 2: $\frac{81}{7}$
Option 3: $\frac{71}{8}$
Option 4: $\frac{81}{8}$
Question : If $\left(3 y+\frac{3}{y}\right)=8$, then find the value of $\left(y^2+\frac{1}{y^2}\right)$.
Option 1: $5\frac{1}{9}$
Option 2: $4\frac{5}{6}$
Option 3: $7\frac{1}{9}$
Option 4: $9\frac{1}{9}$
Question : What is the value of $\left(\mathrm{k}+\frac{1}{\mathrm{k}}\right)\left(\mathrm{k}-\frac{1}{\mathrm{k}}\right)\left(\mathrm{k}^2+\frac{1}{\mathrm{k}^2}\right)\left(\mathrm{k}^4+\frac{1}{\mathrm{k}^4}\right)$?
Option 1: $\mathrm{k}^{16}+\frac{1}{\mathrm{k}^{16}}$
Option 2: $\mathrm{k}^{16}-\frac{1}{\mathrm{k}^{16}}$
Option 3: $\mathrm{k}^8-\frac{1}{\mathrm{k}^8}$
Option 4: $\mathrm{k}^8+\frac{1}{\mathrm{k}^8}$
Question : If $\left(4y-\frac{4}{y}\right)=11$, find the value of $\left(y^2+\frac{1}{y^2}\right)$.
Option 1: $7 \frac{9}{16}$
Option 2: $5 \frac{9}{16}$
Option 3: $9 \frac{11}{16}$
Option 4: $9 \frac{9}{16}$
Question : If $\left (a+b \right):\left (b+c \right):\left (c+a \right)= 6:7:8$ and $\left (a+b+c \right) = 14,$ then value of $c$ is:
Option 1: 6
Option 2: 7
Option 3: 8
Option 4: 14
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