B

9000064104

Level: 
B
Let \(p\) be the tangent to the graph of the function \(f(x) = x^{2} - x - 6\) parallel to the line \(y = 3x + 1\). Find the point \(A\) where \(p\) touches the graph of \(f\).
\(A = \left [2;-4\right ]\)
\(A = \left [2;4\right ]\)
\(A = \left [1;6\right ]\)
\(A = \left [-1;-4\right ]\)

9000063809

Level: 
B
Given the sequence \(\left ( \frac{1} {n(n+1)}\right )_{n=1}^{\infty }\), find the recurrence relation for this sequence.
\(a_{n+1} = \frac{n} {n+2}a_{n},\ a_{1} = \frac{1} {2}\)
\(a_{n+1} = \frac{n} {n+1}a_{n},\ a_{1} = \frac{1} {2}\)
\(a_{n+1} = \frac{n+1} {n} a_{n},\ a_{1} = \frac{1} {2}\)
\(a_{n+1} = \frac{n+1} {n+2}a_{n},\ a_{1} = \frac{1} {2}\)

9000062906

Level: 
B
A semicircle is a half of the full circle. An infinite spiral is built from semicircles with a decreasing radius. The radius of the first semicircle is \(2\, \mathrm{cm}\). The radius of each semicircle in the spiral is one half of the radius of the previous semicircle. Find the total length of the spiral.
\(4\pi \)
\(\frac{4} {3}\pi \)
\(- 4\pi \)
\(\infty \)

9000062908

Level: 
B
A quarter circle is an arc formed by one quarter of the full circle. An infinite spiral is built from quarter circles with an increasing radius. The radius of the first quarter circle is \(4\, \mathrm{cm}\). The radius of each quarter circle in the spiral is one half of the radius of the previous quarter circle. Find the total length of the spiral.
\(4\pi \)
\(8\)
\(\frac{8} {3}\)
\(\infty \)