Draw a function image：

y=x²-8;10x+28.3

Draw a function image：

y=2cos(π/2)

Draw a function image：

y=2cos(2x-π/4);cosx;

Draw a function image：

y=lnx;-1/x

Draw a function image：

y=40.31+73.37sinx+12.63cosx+58sin2x+174cos2x+176sin3x+39.407cos3x
y=38.19+79.38sinx+11.17cosx+62sin2x+156cos2x+165sin3x+46.08cos3x
y=34.65+73.37sinx+10.08cosx+76sin2x+168cos2x+168sin3x+50.388cos3x
y=31.12+89.47sinx+11.37cosx+62sin2x+178cos2x+182sin3x+44.609cos3x