Quadratic Equations with Complex Roots

2010013301

Level: 
B
Find the set of all complex roots of the following quadratic equation. \[ x^2 - 2x + 2 = 0 \]
\( \left\{ \sqrt2\left(\cos\frac{\pi}4+\mathrm{i}\cdot\sin\frac{\pi}4\right); \sqrt2\left(\cos\frac{7\pi}4+\mathrm{i}\cdot\sin\frac{7\pi}4\right) \right\} \)
\( \left\{ 2\left(\cos\frac{\pi}4+\mathrm{i}\cdot\sin\frac{\pi}4\right); 2\left(\cos\frac{7\pi}4+\mathrm{i}\cdot\sin\frac{7\pi}4\right) \right\} \)
\( \left\{ \sqrt2\left(\cos\frac{\pi}4+\mathrm{i}\cdot\sin\frac{\pi}4\right); \sqrt2\left(\cos\frac{3\pi}4+\mathrm{i}\cdot\sin\frac{3\pi}4\right) \right\} \)
\( \left\{ \sqrt2\left(\cos\frac{\pi}4+\mathrm{i}\cdot\sin\frac{\pi}4\right); \sqrt2\left(\cos\frac{5\pi}4+\mathrm{i}\cdot\sin\frac{5\pi}4\right) \right\} \)

2010013208

Level: 
C
Which of the given quadratic equations has the roots \( x_1 = -1 - 3\mathrm{i} \) and \( x_2 = 1 +3\mathrm{i} \)?
\( x^2 + (3 - 3\mathrm{i}) + 5 - 3\mathrm{i} = 0 \)
\( x^2 - (3 - 3\mathrm{i}) + 5 + 3\mathrm{i} = 0 \)
\( x^2 + (3 - 3\mathrm{i}) + 5 + 3\mathrm{i} = 0 \)
\( x^2 - (3 - 3\mathrm{i}) + 5 - 3\mathrm{i} = 0 \)

2010013207

Level: 
C
Find the complex roots of the following quadratic equation. \[ 2x^2 + 5\mathrm{i} = 0 \]
\( x_1=-\frac{\sqrt5}2+\frac{\sqrt5}2\mathrm{i},\ \ x_2=\frac{\sqrt5}2-\frac{\sqrt5}2\mathrm{i} \)
\( x_1=\frac{\sqrt5}2+\frac{\sqrt5}2\mathrm{i},\ \ x_2=-\frac{\sqrt5}2-\frac{\sqrt5}2\mathrm{i} \)
\( x_1=\frac{\sqrt5}2\mathrm{i},\ \ x_2=-\frac{\sqrt5}2\mathrm{i} \)
\( x_1=-\frac{\sqrt5}2,\ \ x_2=\frac{\sqrt5}2\)

2010013206

Level: 
C
Find the complex roots of the following quadratic equation. \[ 3\mathrm{i}x^2 + 2 = 0 \]
\( x_1=\frac{\sqrt3}3+\frac{\sqrt3}3\mathrm{i},\ \ x_2=-\frac{\sqrt3}3-\frac{\sqrt3}3\mathrm{i} \)
\( x_1=-\frac{\sqrt3}3+\frac{\sqrt3}3\mathrm{i},\ \ x_2=\frac{\sqrt3}3-\frac{\sqrt3}3\mathrm{i} \)
\( x_1=-\frac{\sqrt3}6+\frac{\sqrt3}6\mathrm{i},\ \ x_2=-\frac{\sqrt3}6-\frac{\sqrt3}6\mathrm{i} \)
\( x_1=\frac{\sqrt3}6+\frac{\sqrt3}6\mathrm{i},\ \ x_2=-\frac{\sqrt3}6-\frac{\sqrt3}6\mathrm{i} \)

2010013205

Level: 
C
Find the complex roots of the following quadratic equation. \[ (2-\mathrm{i})x^2-(3-2\mathrm{i})x = 0 \]
\( x_1=\frac85-\frac15\mathrm{i},\ \ x_2=0 \)
\( x_1=\frac85+\frac15\mathrm{i},\ \ x_2=0 \)
\( x_1=-\frac85-\frac15\mathrm{i},\ \ x_2=0 \)
\( x_1=-\frac85+\frac15\mathrm{i},\ \ x_2=0 \)