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).
Due to this similarity, any cosine function can be written in terms of a sine function as cos x=sin (x+ Ï/2). There is also no difference in the frequency of a cosine and its corresponding sine wave. Both have a maximum of 1 and a minimum of -1. Sine function curve stats at 0 and then moves upward to 1 by Ï/2 radians and then comes back to -1.