A

1103018905

Level: 
A
In the cube \( ABCDEFGH \) with \( S_{AC} \) being the midpoint of the diagonal \( AC \), let \( \varphi \) be the angle between the line \( EG \) and the line \( GS_{AC} \). Choose the correct expression for \( \varphi \):
\( \mathrm{tg}\,\varphi = \sqrt2 \)
\( \mathrm{sin}\,\varphi = \frac{\sqrt3}3 \)
\( \mathrm{tg}\,\varphi = \frac{\sqrt2}2 \)
\( \mathrm{cos}\,\varphi = \frac{\sqrt6}3 \)

1103018903

Level: 
A
In the cube \( ABCDEFGH \) with \( S_{AC} \) being the midpoint of the diagonal \( AC \), let \( \varphi \) be the angle between the line \( ES_{AC} \) and the bottom face \( ABCD \). Choose the correct expression for \( \varphi \).
\( \mathrm{tg}\,\varphi = \sqrt2 \)
\( \mathrm{sin}\,\varphi = \frac{\sqrt2}3 \)
\( \mathrm{tg}\,\varphi = \frac{\sqrt2}2 \)
\( \mathrm{cos}\,\varphi = \frac{\sqrt6}3 \)

1103018902

Level: 
A
Let \( \varphi \) bet the angle between a space diagonal of a cube and its face diagonal. Choose the correct expression for \( \varphi \).
\( \mathrm{tg}\,\varphi = \frac{\sqrt2}2 \)
\( \mathrm{sin}\,\varphi = \frac{\sqrt2}2 \)
\( \mathrm{tg}\,\varphi = \frac{\sqrt3}3 \)
\( \mathrm{tg}\,\varphi = \frac{\sqrt6}3 \)

1103024310

Level: 
A
The picture shows the triangle \( KLM \) with indicated vectors \( \overrightarrow{a} \), \( \overrightarrow{b} \), \( \overrightarrow{c} \) in a coordinate system. What are the vector coordinates \( \overrightarrow{b} \)? Express \( \overrightarrow{b} \) as a linear combination of \( \overrightarrow{a} \) and \( \overrightarrow{c} \).
\( \overrightarrow{b} = \left(1;3;4.5\right);\ \overrightarrow{b} = \frac12\overrightarrow{a} + \frac12\overrightarrow{c} \)
\( \overrightarrow{b} = \left(3;1;4.5\right);\ \overrightarrow{b} = \overrightarrow{a} + \overrightarrow{c} \)
\( \overrightarrow{b} = \left(1;3;4.5\right);\ \overrightarrow{b} = \overrightarrow{a} + \overrightarrow{c} \)
\( \overrightarrow{b} = \left(3;1;4.5\right);\ \overrightarrow{b} = \frac12\overrightarrow{a} + \frac12\overrightarrow{c} \)

1103024309

Level: 
A
Given the vectors \( \overrightarrow{a} \), \( \overrightarrow{b} \), \( \overrightarrow{c} \) shown in the picture, express a vector \( \overrightarrow{b} \) as a linear combination of vectors \( \overrightarrow{a} \) and \( \overrightarrow{c} \).
\( \overrightarrow{b} = 2\overrightarrow{a} + \overrightarrow{c} \)
\( \overrightarrow{b} = 2\overrightarrow{a} - \overrightarrow{c} \)
\( \overrightarrow{b} = -2\overrightarrow{a} + \overrightarrow{c} \)
\( \overrightarrow{b} = -2\overrightarrow{a} - \overrightarrow{c} \)