Cobb-Douglas  Function

Clear[x1, x2, ρ]; 
ρ = 0.7; 
CD = x1^ρ*x2^(1 - ρ); 
Plot3D[CD, {x1, 0, 1}, {x2, 0, 1}]
ContourPlot[CD, {x1, 0, 1}, {x2, 0, 1}]