# List of functions used for tangent/normal 2D.
# An item in this list will be picked randomly at each exercise.
# Structure of item: multi-line.
# line 1 is function description.
# line 2 is derivative.
# line 3 is proportionality
# The rest is values for parameters c1, c2, etc.

:c1*y*x*sin(c2*x)
c1*y*sin(c2*x)+c1*y*x*c2*cos(c2*x),c1*x*sin(c2*x)
 1.2
 -0.8,-0.7,-0.6,-0.5,-0.4,0.4,0.5,0.6,0.7,0.8
 -0.8,-0.7,-0.6,-0.5,-0.4,0.4,0.5,0.6,0.7,0.8
:c1*y*x*exp(c2*x*y)
c1*y*exp(c2*x*y)+c1*c2*y^2*x*exp(c2*x*y),c1*x*exp(c2*x*y)+c1*c2*x^2*y*exp(c2*x*y)
 1.2
 -0.8,-0.7,-0.6,-0.5,-0.4,0.4,0.5,0.6,0.7,0.8
 -0.8,-0.7,-0.6,-0.5,-0.4,0.4,0.5,0.6,0.7,0.8
:c1*sin(x)*exp(c2*y-x)
c1*cos(x)*exp(c2*y-x)-c1*sin(x)*exp(c2*y-x),c1*sin(x)*c2*exp(c2*y-x)
 1.2
 -0.8,-0.7,-0.6,-0.5,-0.4,0.4,0.5,0.6,0.7,0.8
 -0.8,-0.7,-0.6,-0.5,-0.4,0.4,0.5,0.6,0.7,0.8
