f(x):=((e^-ax^2)-bxln(1+x^2))/(2+x^2+csin(Pi*x))

i have defined a,b and c. (all randoms numbers between 0 and 1 )

But when i try to plot it

plot((f(x)), x=-4..4) i get ( warning unabe to evaluate function to numeric values ion the region)

also i can plot the graph even without a range included ???

What am i doing wrong, have i defined f(x) right. thanks in advance

also i can plot the graph even without a range included ???