Sine wave & reflection question?

[shintashi]

I seem to recall it is possible to change a wave's frequency, pattern, and amplitude by adding another wave to it.

Is it possible to add a second wave to a Sine wave to turn it into a cosine wave of the same amplitude and how would you do this? I'm thinking if I had an amplitude 1 for the sinewave, an amplitude 2 cosine wave would wipe out the sine wave and be reduced to a cosine wave. Is there a simpler way of doing this requiring less amplitude?

As a side note on waves, is there a good place/website to understand the physics behind reflection?

 

[HallsofIvy]

This is a question, not "learning materials" so I am moving this to "Introductory Physics".

 

[JaWiB]

So you think sin(x)+2cos(x) = cos(x)?

If this were true, then sin(x) = -cos(x) would also be true (which it isn't). What you're probably thinking of is the http://physics.tamuk.edu/~suson/html/4323/super.html.

I'm not sure what specifically you're looking for in regards to reflection (sound? light? mechanical waves?), but a couple of sites that have been handy for me are hyperphysics and PhET (I seem to recall a simulation or two involving waves/pulses on a string)