I am unable to plot a function of two variables f(x,y). Kindly, some one help me plot this function. Mathematica file is attached here.
u[x_] := Exp[-4 (x - 1)^2]
?[x_] := Exp[-Integrate[u[y]/0.2, {y, 0, x}]]
f[x_, t_] := Integrate[(x - z)/t ?[z] Exp[-(x - z)^2/(0.4 t)], {z, -?, ?}]/
Integrate[?[z] Exp[-(x - z)^2/(0.4 t)], {z, -?, ?}]
Plot3D[f[x, t], {x, 1, 3}, {t, 1, 3}]
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