A cactus (plural: cacti, cactuses, or cactus) is a member of the plant family Cactaceae,[Note 1] a family comprising about 127 genera with some 1750 known species of the order Caryophyllales.
'cot' and 'crib' In British English, a cot is a bed for a baby. A cot has high sides to prevent the baby from falling out. In American English, a bed like this is called a crib.
The proper definition of [math]\cot x[/math] is. [math]\cot x = \sum_{n=0}^{\infty} \frac{(-1)^n 2^{2n} B_{2n} x^{2n-1}}{(2n)!}[/math] But since that probably doesnât mean much to you, simply it is indeed [math]\frac{\cos x}{\sin x}[/math] as youâve been taught.