Question 1
Find all value ranges of $x$ for which $$
\cos x+\operatorname{sen} x\gt 1
$$ same problem for $$
\cos x+|\operatorname{sen} x|\gt 1
$$
\cos x+\operatorname{sen} x\gt 1
$$ same problem for $$
\cos x+|\operatorname{sen} x|\gt 1
$$
Math Olympiad Vault · MathNet 1964 — Part 01