Basis functions(why sine and cosine only)

[rachitag]

We use sine and cosine as basis functions. Why we can not have more than this. May be other than this. For orthogonal implementations we are dependent on orthogonal frequencies and these two basis function. Is there any process by which we can create or consider more than this. Then we can have more spectral efficiency.

 

[greygoo2012]

I hope I've understood your question correctly.

Sine and cosine are not two different basis functions. One is derived from shifting the other by pi/2. These become orthogonal on a 2-D plane. Similarly, 'N' such orthogonal signals can be created for an N dimensional space.

 

[Warpspeed]

Not only that, we live in a world full of sine wave functions.
Sines and cosines are the very basis of describing sine waves mathematically.