This gives the meaning of the terms as generally understood in the middle of the 18th century. Robert Hooper's Physician's Vade-Mecum, published in 1812 has been used as a source of terms in the early 19th century; many of the terms mentioned are still in common use.
In either case, the value at x = 0 is defined to be the limiting value sinc(0) = 1. The normalization causes the definite integral of the function over the real numbers to equal 1 (whereas the same integral of the unnormalized sinc function has a value of Ï).
So, if w is a fixed number and q is any angle we have the following periods. sin (wq) ï¬ 2 Tpw = cos (wq) ï¬ 2 Tpw = tan (wq) ï¬ Tpw = csc (wq) ï¬ 2 Tpw = sec (wq) ï¬ 2 Tpw = cot (wq) ï¬ Tpw = q adjacent opposite hypotenuse x y (xy,) q x y 1.