Question

If $$z = \frac{\pi }{4}{\left( {1 + i} \right)^4}\left( {\frac{{1 - \sqrt \pi i}}{{\sqrt \pi + i}} + \frac{{\sqrt \pi - i}}{{1 + \sqrt \pi i}}} \right),$$        then $$\left( {\frac{{\left| z \right|}}{{amp\left( z \right)}}} \right)$$  equals

A. $$1$$
B. $$\pi$$
C. $$3\pi$$
D. $$4$$  
Answer :   $$4$$
Solution :
$$\eqalign{ & z = \frac{\pi }{4}{\left( {1 + i} \right)^4}\left( {\frac{{1 - \sqrt \pi i}}{{\sqrt \pi + i}} + \frac{{\sqrt \pi - i}}{{1 + \sqrt \pi i}}} \right) \cr & = \frac{\pi }{4}{\left( {1 + i} \right)^4}\left[ {\frac{{1 + \pi + \pi + 1}}{{\left( {\sqrt \pi + i} \right)\left( {1 + \sqrt \pi i} \right)}}} \right] = \frac{\pi }{4}{\left( {1 + i} \right)^4}\frac{2}{i} \cr & = \frac{\pi }{4}{\left( {2i} \right)^2}\frac{2}{i} = 2\pi i \cr & \therefore \left( {\frac{{\left| z \right|}}{{amp\left( z \right)}}} \right) = \frac{{2\pi }}{{\frac{\pi }{2}}} = 4 \cr} $$

Releted MCQ Question on
Algebra >> Complex Number

Releted Question 1

If the cube roots of unity are $$1,\omega ,{\omega ^2},$$  then the roots of the equation $${\left( {x - 1} \right)^3} + 8 = 0\,\,{\text{are}}$$

A. $$ - 1,1 + 2\omega ,1 + 2{\omega ^2}$$
B. $$ - 1,1 - 2\omega ,1 - 2{\omega ^2}$$
C. $$- 1, - 1, - 1$$
D. none of these
Releted Question 2

The smallest positive integer $$n$$ for which $${\left( {\frac{{1 + i}}{{1 - i}}} \right)^n} = 1\,{\text{is}}$$

A. $$n = 8$$
B. $$n = 16$$
C. $$n = 12$$
D. none of these
Releted Question 3

The complex numbers $$z = x+ iy$$   which satisfy the equation $$\left| {\frac{{z - 5i}}{{z + 5i}}} \right| = 1$$   lie on

A. the $$x$$ - axis
B. the straight line $$y = 5$$
C. a circle passing through the origin
D. none of these
Releted Question 4

If $$z = {\left( {\frac{{\sqrt 3 }}{2} + \frac{i}{2}} \right)^5} + {\left( {\frac{{\sqrt 3 }}{2} - \frac{i}{2}} \right)^5},\,{\text{then}}$$

A. $${\text{Re}}\left( z \right) = 0$$
B. $${\text{Im}}\left( z \right) = 0$$
C. $${\text{Re}}\left( z \right) > 0,{\text{Im}}\left( z \right) > 0$$
D. $${\text{Re}}\left( z \right) > 0,{\text{Im}}\left( z \right) < 0$$

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Complex Number


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