Acos(2 pi f1 t) + B cos (2 pi f2 t) =?

Question

can anybody find a webpage that shows the answer to this? or can anybody explain how the A and B and f1 and f2 are related once added?

ehhh no. I'm just looking for the answer in terms of the same variables given.

is the answer just A+B cos(4 pi t f1+f2)? what happens to the frequencies and the amplitues.. that's what I'm looking for.

Answer 1

If you put A / sqrt(A^2 + B^2) = sin(2 pi f2 t)
and B / sqrt(A^2 + B^2) = sin(2 pi f1 t), then the expression becomes equivalent to:
sqrt(A^2 + B^2) sin( 2 pi (f1 + f2)t ).
Is that any help?

Answer 2

A and B are the amplitudes of the two cos waves and 2pif is the angular ritation measured in radians/second. t is time measured in seconds. The period is 1/f.

All you can do is plot each cos wave separately on the same set of axes and then add there ordiantes. You could do this on a TI 83 calculator.

Try this web site:
http://intmath.com/Trigonometric-graphs/6_Composite-trigonometric-graphs.php