- #1

billyd690

- 3

- 0

f(x,y) = cos(x+y)exp(x^2 - y^2) @ point (0.5,-0.5)

&

f(x,y) = sin(exp(xy)) @ point (1,1)

My code for the two are as follows respectively:

Clear[f,x,y,fx,fy,point1,point2]

point1=0.5;

point2=-0.5;

f[x_,y_]=cos(x+y)exp((x^2) - (y^2));

fx[x_,y_]=D[f[x,y],x];

fy[x_,y_]=D[f[x,y],y];

T[x_,y_]:=f[point1,point2]+fx[point1,point2](x-point1)+fy[point1,point2](y-point2)

T[x,y]

Clear[G1,G2];

G1=Plot3D[f[x,y],{x,-2,10},{y,-4,4}]

G2=Plot3D[T[x,y],{x,-2,10},{y,-4,4}]

Show[G1,G2,ViewPoint -> {0,-2,0.3},AspectRatio -> 1,AxesLabel -> {"x","y","f(x,y)"}]

for the second:

Clear[f,x,y,fx,fy,point1,point2]

point1=1;

point2=1;

f[x_,y_]= sin(exp(xy));

fx[x_,y_]=D[f[x,y],x];

fy[x_,y_]=D[f[x,y],y];

T[x_,y_]:=f[point1,point2]+fx[point1,point2](x-point1)+fy[point1,point2](y-point2)

T[x,y]

Clear[G1,G2];

G1=Plot3D[f[x,y],{x,-2,10},{y,-4,4}]

G2=Plot3D[T[x,y],{x,-2,10},{y,-4,4}]

Show[G1,G2,ViewPoint -> {0,-2,0.3},AspectRatio -> 1,AxesLabel -> {"x","y","f(x,y)"}]

I believe the outputs I'm getting are wrong. For the cos one it just plots a flat plane at 0. For the second one there isn't any plot. I've changed around the intervals and viewpoints, but still nothing shows up. Just looking for a little insight into the issue. thanks!