Question : If $\sqrt5=2.236$, then what is the value of $\frac{\sqrt5}{2}+\frac{5}{3\sqrt5}-\sqrt{45}$?
Option 1: – 8.571
Option 2: – 4.845
Option 3: – 2.987
Option 4: – 6.261
Correct Answer: – 4.845
Solution : Given: $\sqrt{5} = 2.236$ $\frac{\sqrt{5}}{2} + \frac{5}{3\sqrt{5}} - \sqrt{45}$ Now evaluate the equation, = $ \frac{\sqrt{5}\times3\sqrt{5} + 5\times2-3\sqrt{5}\times2\times3\sqrt{5}}{2\times3\sqrt{5}}$ = $ \frac{15 + 10 - 90}{2\times3\sqrt{5}}$ = $ -\frac{65}{2\times3\sqrt{5}}$ Rationalising the fraction = $ -\frac{65\sqrt{5}}{30}$ Put the value of $\sqrt{5} = 2.236$ = $-\frac{65\times 2.236}{30} = -4.845$ Hence, the correct answer is – 4.845.
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Question : If $\frac{1}{N}=\frac{(\sqrt6+\sqrt5)}{(\sqrt6-\sqrt5)}$, what is the value of $N$?
Option 1: $6-\sqrt{30}$
Option 2: $6+\sqrt{30}$
Option 3: $11-2\sqrt{30}$
Option 4: $11+2\sqrt{5}$
Question : If $\sin A=\frac{1}{2}$, then the value of $(\tan A+\cos A)$ is:
Option 1: $\frac{2}{3 \sqrt{3}}$
Option 2: $\frac{3}{2 \sqrt{3}}$
Option 3: $\frac{5}{2 \sqrt{3}}$
Option 4: $\frac{5}{3 \sqrt{3}}$
Question : If $\sin (A-B)=\sin A \cos B–\cos A\sin B$, then $\sin 15°$ will be:
Option 1: $\frac{\sqrt{3}+1}{2\sqrt{2}}$
Option 2: $\frac{\sqrt{3}}{2\sqrt{2}}$
Option 3: $\frac{\sqrt{3}–1}{–\sqrt{2}}$
Option 4: $\frac{\sqrt{3}–1}{2\sqrt{2}}$
Question : If $a-\frac{1}{a}=4$, then the value of $a+\frac{1}{a}$ is:
Option 1: $5 \sqrt{5}$
Option 2: $4 \sqrt{5}$
Option 3: $2 \sqrt{5}$
Option 4: $3 \sqrt{5}$
Question : If $x^2+\frac{1}{x^2}=\frac{7}{4}$ for $x>0$, what is the value of $(x^3+\frac{1}{x^3})$?
Option 1: $\frac{3\sqrt{3}}{5}$
Option 2: $\frac{3\sqrt{15}}{5}$
Option 3: $\frac{3\sqrt{15}}{8}$
Option 4: $\frac{3\sqrt{5}}{8}$
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