C

9000036103

Level: 
C
Three forces \(F_{1}\), \(F_{2}\) and \(F_{3}\) act on the same body in the same point and the total force on the body is zero (the forces cancel). The first two forces are \(F_{1} = 8\, \mathrm{N}\) and \(F_{2} = 10\, \mathrm{N}\) and the angle between \(F_{1}\) and \(F_{2}\) is \(55^{\circ }\). Find the angle between \(F_{3}\) and \(F_{1}\). Round your answer to the nearest degrees.
\(149^{\circ }\)
\(125^{\circ }\)
\(55^{\circ }\)
\(30^{\circ }\)

9000036106

Level: 
C
Two straight roads go off from the crossing. The angle between directions of the roads is \(52^{\circ }18'\). A significant tree is on the first road in the distance \(250\, \mathrm{m}\) from the crossing. A rock with a beautiful view is on the second road in the distance \(380\, \mathrm{m}\) from the crossing. Find the direct distance (length of a line segment) from the rock to the tree and round your answer to nearest meters.
\(301\, \mathrm{m}\)
\(411\, \mathrm{m}\)
\(568\, \mathrm{m}\)
\(629\, \mathrm{m}\)

9000035602

Level: 
C
Find the values of the parameter \(m\in \mathbb{C}\) which guarantee that the following quadratic equation has a double solution. \[ mx^{2} - 2x - 1 + \mathrm{i} = 0 \]
\(m = -\frac{1} {2} -\frac{1} {2}\mathrm{i}\)
\(m = -1\)
\(m = -1 + \mathrm{i}\)
\(m = -\frac{1} {2} + \frac{1} {2}\mathrm{i}\)

9000035609

Level: 
C
One of the roots of the equation \( x^{2} + px - 11 = 0\) with the parameter \(p\in \mathbb{C}\) is \(x_{1} = 3 -\mathrm{i}\sqrt{2}\). Find the second root \(x_{2}\) and the corresponding value of the parameter \(p\).
\(x_{2} = -3 -\mathrm{i}\sqrt{2},\ p = 2\mathrm{i}\sqrt{2}\)
\(x_{2} = 3 + \mathrm{i}\sqrt{2},\ p = 6\)
\(x_{2} = -3 -\mathrm{i}\sqrt{2},\ p = 6\)
\(x_{2} = 3 + \mathrm{i}\sqrt{2},\ p = -2\mathrm{i}\)
\(x_{2} = -3 -\mathrm{i}\sqrt{2},\ p = -2\mathrm{i}\sqrt{2}\)

9000034303

Level: 
C
Find the solution set of the following equation in the set of complex numbers. \[ x^{3} + \mathrm{i} = 0 \]
\(\{\mathrm{i};\ \frac{\sqrt{3}} {2} -\frac{1} {2}\mathrm{i};\ -\frac{\sqrt{3}} {2} -\frac{1} {2}\mathrm{i}\}\)
\(\{ - 1;\ -\frac{\sqrt{3}} {2} + \frac{1} {2}\mathrm{i};\ -\frac{\sqrt{3}} {2} -\frac{1} {2}\mathrm{i}\}\)
\(\{ - 1;\ \frac{\sqrt{3}} {2} -\frac{1} {2}\mathrm{i};\ -\frac{\sqrt{3}} {2} -\frac{1} {2}\mathrm{i}\}\)
\(\{\mathrm{i};\ -\frac{\sqrt{3}} {2} + \frac{1} {2}\mathrm{i};\ -\frac{\sqrt{3}} {2} -\frac{1} {2}\mathrm{i}\}\)

9000034308

Level: 
C
Two solutions of the equation \[ x^{3} + 1 + \mathrm{i} = 0 \] are \[ \begin{aligned}x_{1}& = \root{6}\of{2}\left (\cos \frac{5} {12}\pi + \mathrm{i}\sin \frac{5} {12}\pi \right ),& \\x_{2}& = \root{6}\of{2}\left (\cos \frac{13} {12}\pi + \mathrm{i}\sin \frac{13} {12}\pi \right ). \\ \end{aligned} \] Find the third solution.
\(x_{3} = \root{6}\of{2}\left (\cos \frac{21} {12}\pi + \mathrm{i}\sin \frac{21} {12}\pi \right )\)
\(x_{3} = \root{6}\of{2}\left (\cos \frac{9} {12}\pi + \mathrm{i}\sin \frac{9} {12}\pi \right )\)
\(x_{3} = \root{6}\of{2}\left (\cos \frac{17} {12}\pi + \mathrm{i}\sin \frac{17} {12}\pi \right )\)
\(x_{3} = \root{6}\of{2}\left (\cos \frac{19} {12}\pi + \mathrm{i}\sin \frac{19} {12}\pi \right )\)