B

9000038907

Level: 
B
Consider the function \(f(x) =\mathop{\mathrm{cotg}}\nolimits x\) with domain restricted to the interval \(\mathop{\mathrm{Dom}}(f) = (0;\pi )\). In the following list identify the function with domain \(\left (0; \frac{\pi } {3}\right )\).
\(f(3\cdot x)\)
\(f(x - 3)\)
\(f(x + 3)\)
\(f\left (\frac{x} {3} \right )\)
\(3\cdot f(x)\)

9000037510

Level: 
B
Given complex numbers \[ a = \left (\cos \frac{\pi } {3} + \mathrm{i}\sin \frac{\pi } {3}\right ),\quad b = \sqrt{2}\left (\cos \frac{2\pi } {3} + \mathrm{i}\sin \frac{2\pi } {3}\right ) \] find the quotient \(\frac{a} {b}\).
\(\frac{\sqrt{2}} {2} \left (\cos \left (-\frac{\pi } {3}\right ) + \mathrm{i}\sin \left (-\frac{\pi } {3}\right )\right )\)
\(\frac{\sqrt{2}} {2} \left (\cos \left (-\frac{\pi } {3}\right ) -\mathrm{i}\sin \left (-\frac{\pi } {3}\right )\right )\)
\(-\frac{\sqrt{2}} {2} \left (\cos \left (-\frac{\pi } {3}\right ) -\mathrm{i}\sin \left (-\frac{\pi } {3}\right )\right )\)
\(-\frac{\sqrt{2}} {2} \left (\cos \left (-\frac{\pi } {3}\right ) + \mathrm{i}\sin \left (-\frac{\pi } {3}\right )\right )\)

9000038601

Level: 
B
Find the polar form of the following complex number. \[ -\frac{1} {2} + \mathrm{i}\frac{\sqrt{3}} {2} \]
\(\cos \frac{2\pi } {3} + \mathrm{i}\sin \frac{2\pi } {3}\)
\(\cos \frac{\pi } {3} + \mathrm{i}\sin \frac{\pi } {3}\)
\(\cos \left (-\frac{\pi }{3}\right ) + \mathrm{i}\sin \left (-\frac{\pi }{3}\right )\)
\(\cos \frac{3\pi } {2} + \mathrm{i}\sin \frac{3\pi } {2}\)

9000038602

Level: 
B
Find the polar form of the following complex number. \[ \frac{1} {2} + \mathrm{i}\frac{\sqrt{3}} {2} \]
\(\cos \frac{\pi }{3} + \mathrm{i}\sin \frac{\pi }{3}\)
\(\cos \frac{2\pi } {3} + \mathrm{i}\sin \frac{2\pi } {3}\)
\(\cos \frac{3\pi } {2} + \mathrm{i}\sin \frac{3\pi } {2}\)
\(\cos \left (-\frac{\pi }{3}\right ) + \mathrm{i}\sin \left (-\frac{\pi }{3}\right )\)

9000038603

Level: 
B
Find the polar form of the following complex number. \[ \frac{\sqrt{2}} {2} + \mathrm{i}\frac{\sqrt{6}} {2} \]
\(\sqrt{2}\left (\cos \frac{\pi }{3} + \mathrm{i}\sin \frac{\pi }{3}\right )\)
\(\sqrt{2}\left (\cos \frac{2\pi } {3} + \mathrm{i}\sin \frac{2\pi } {3}\right )\)
\(2\left (\cos \frac{4\pi } {3} + \mathrm{i}\sin \frac{4\pi } {3}\right )\)
\(2\left (\cos \frac{3\pi } {2} + \mathrm{i}\sin \frac{3\pi } {2}\right )\)

9000038604

Level: 
B
Find the polar form of the following complex number. \[ \frac{\sqrt{3}} {\sqrt{2}} + \mathrm{i}\frac{\sqrt{3}} {\sqrt{2}} \]
\(\sqrt{3}\left (\cos \frac{\pi }{4} + \mathrm{i}\sin \frac{\pi }{4}\right )\)
\(\sqrt{3}\left (\cos \frac{3\pi } {4} + \mathrm{i}\sin \frac{3\pi } {4}\right )\)
\(\sqrt{2}\left (\cos \frac{\pi }{3} + \mathrm{i}\sin \frac{\pi }{3}\right )\)
\(\sqrt{2}\left (\cos \frac{2\pi } {3} + \mathrm{i}\sin \frac{2\pi } {3}\right )\)

9000038605

Level: 
B
Find the polar form of the following complex number. \[ -\frac{\sqrt{5}} {2} + \mathrm{i}\frac{\sqrt{15}} {2} \]
\(\sqrt{5}\left (\cos \frac{2\pi } {3} + \mathrm{i}\sin \frac{2\pi } {3}\right )\)
\(\sqrt{5}\left (\cos \frac{\pi }{3} + \mathrm{i}\sin \frac{\pi }{3}\right )\)
\(\sqrt{5}\left (\cos \frac{2\pi } {5} + \mathrm{i}\sin \frac{2\pi } {5}\right )\)
\(\sqrt{5}\left (\cos \frac{3\pi } {2} + \mathrm{i}\sin \frac{3\pi } {2}\right )\)

9000038606

Level: 
B
Find the algebraic form of the following complex number. \[ \cos \frac{\pi } {4} + \mathrm{i}\sin \frac{\pi } {4} \]
\(\frac{\sqrt{2}} {2} + \mathrm{i}\frac{\sqrt{2}} {2} \)
\(\frac{\sqrt{2}} {2} -\mathrm{i}\frac{\sqrt{2}} {2} \)
\(\frac{\sqrt{3}} {2} + \mathrm{i}\frac{\sqrt{3}} {2} \)
\(\frac{\sqrt{3}} {2} -\mathrm{i}\frac{\sqrt{3}} {2} \)

9000038901

Level: 
B
Consider the function \(f\colon y = A\cdot \sin (B\cdot x + C)\), with real nonzero parameters \(A\), \(B\) and \(C\). Which of the following operations makes the period of the function five times smaller?
Increase \(B\) by a factor \(5\).
Increase \(A\) by a factor \(5\).
Decrease \(A\) by a factor \(5\).
Decrease \(B\) by a factor \(5\).
Increase \(C\) by a factor \(5\).
Decrease \(C\) by a factor \(5\).