Given the functions
\[
\text{$f(x) = -\frac{2}
{x}$ and $g(x)= \frac{k}
{x}$}
\]
find the value of the parameter \(k\in \mathbb{R}\setminus \{0\}\)
which ensures
\[
g(2) = 2f(-2).
\]
Consider the function
\[
f(x) = [x] + 3
\]
on the domain \(\mathop{\mathrm{Dom}}(f) = (1;2)\).
Find the parameters \(a\)
and \(b\)
and a domain of the linear function
\[
g\colon y = ax + b
\]
which ensure that \(f\)
and \(g\)
are identical functions.
\[ \]
Hint: The function \(y = [x]\)
is a floor function: the largest integer less than or equal to
\(x\). For positive
\(x\) it is also called the
integer part of \(x\).
Consider the function
\[
f(x) =\mathop{ \mathrm{sgn}}\nolimits (x - 2)
\]
defined on \(\mathop{\mathrm{Dom}}(f) =\mathbb{R} ^{-}\). Find
the parameters \(a\)
a \(b\) and
domain of the linear function
\[
g(x) = ax + b
\]
which ensure that \(f\)
and \(g\)
are identical functions.
\[ \]
Hint: The function \(y =\mathop{ \mathrm{sgn}}\nolimits (x)\)
is the sign function. The values of sign function is
\(1\) for each
positive \(x\),
\(- 1\) for each
negative \(x\)
and \(0\) if
\(x = 0\).
Identify a function which has the following three properties: it has at least one minimum or maximum, it is an increasing function and the range of this function is the set of all nonnegative numbers.
Paul's home is \(6\, \mathrm{km}\) from
the school. At the time \(t = 0\)
Paul starts to walk from his home to the school along a straight street at a constant
velocity \(5\, \mathrm{km}/\mathrm{h}\).
Find the function which describes Paul's remaining distance to the school as a
function of time.
The price of a goods in a shop is \(\$15\)
per item. The Internet price in an e-shop is cheaper by
\(\$2\) per item. The shipping
cost of the e-shop is \(\$125\).
What is the minimal number of items, which makes the total cost for a transaction
smaller in the e-shop?