Fear of needles Fear of needles Fear of needles, known in medical literature as needle phobia, is the extreme fear of medical procedures involving injections or hypodermic needles. It is occasionally referred to as "aichmophobia" or "belonephobia", although these terms may also refer to a more general fear of sharply pointed objects. It has also been referred to as "trypanophobia", although the origin and proper usage of that term is highly controversial. The condition was officially recognized in 1994 in the DSM-IV (Diagnostic and Statistical Manual, 4th edition) as a specific phobia of blood/injection/injury type. Phobic level responses to injections cause sufferers to
Irrational number number to ratios of continuous magnitude. In his commentary on Book 10 of the "Elements", the Persian mathematician Al-Mahani (d. 874/884) examined and classified quadratic irrationals and cubic irrationals. He provided definitions for rational and irrational magnitudes, which he treated as irrational numbers. He dealt with them freely but explains them in geometric terms as follows: In contrast to Euclid's concept of magnitudes as lines, Al-Mahani considered integers and fractions as rational magnitudes, and square roots and cube roots as irrational magnitudes. He also introduced an arithmetical approach to the concept of irrationality, as he attributes the following to irrational