In addition to sine and cosine, what is the third main function of trigonometry?
Mnemonics in trigonometry Mnemonics in trigonometry In trigonometry, it is common to use mnemonics to help remember trigonometric identities and the relationships between the various trigonometric functions. The "sine", "cosine", and "tangent" ratios in a right triangle can be remembered by representing them as strings of letters, for instance SOH-CAH-TOA in English: One way to remember the letters is to sound them out phonetically (i.e. ). Another method is to expand the letters into a sentence, such as "Some Old Hags Can't Always Hide Their Old Age", "Some Old Hippy Caught Another Hippy Trippin' On Acid", or sentences that might be more appropriate
Sine and cosine transforms inversion formula is usually written as an integral over both negative and positive frequencies. Using the addition formula for cosine, this is sometimes rewritten as where denotes the one-sided limit of as approaches zero from above, and denotes the one-sided limit of as approaches zero from below. If the original function is an even function, then the sine transform is zero; if is an odd function, then the cosine transform is zero. In either case, the inversion formula simplifies. The form of the Fourier transform used more often today is Sine and cosine transforms In mathematics, the Fourier sine and