Question 49322
Yes, sin(x) will equal cos(x) eventually:
{{{graph(600,200,-10,10,-1,1,sin(x),cos(x))}}}
Does sin(x) = cos(x - {{{pi}}}/2) .... Yes
Remember: sin(x - 1) shifts horizontally -c units
sin({{{pi}}}/2) = 0
cos(0) = 0
So, sine is {{{pi}}}/2 to the right of cosine.
Cos(x - {{{pi}}}/2):
{{{graph(600,200,-10,10,-1,1,cos(x - 1.570796327))}}}
Sin(x):
{{{graph(600,200,-10,10,-1,1,sin(x))}}}