4. Is the number $\operatorname{tg} \sqrt{5 \pi}-1$ positive or negative? 

#
# Solution.

$$
\text { We will prove that } \frac{5 \pi}{4}0$.

Answer: positive.

Instructions. Only the answer - 0 points; if the inequality (1) for $\pi$ uses an approximate value of 3.14 (after squaring) - 4 points; the square root is found approximately, for example, using a calculator - 0 points.
$$