2. 3 Math and Visualization 13 To find the partial derivative of f with respect to y At the prompt, enter the following and press ENTER. Since you are interested in the real solution, use the f l ve command instead of the more general solve command To solve the system of equations [fx=0, fy=0: At the prompt, enter the following and press ENTER. top_Xy:= fsolve({fx=0,fy=0},{x,y},{x=-3..0,y=-3..0}) The top of the hill is therefore at approximately (x=-.9026100199 y=-1.805220040 Note: Sets do not preserve order, so you may instead obtain the equivalent set 【y=-1.805220040,X=-.9026100199} Finding the skiers starting point Assume that the skier does not start at the peak but slightly to the side. To approximate this location, add a small factor, say 0. 05, to the x-and y values. Assign these values to the variables x and y and then add the approximating factor. To assign the values to the variables: At the prompt, enter the following and press ENTER. assign (%) The ditto operator(%)refers to the result of the previous computation. For more information, refer to %(The ditto operators To define the starting x-and y-values, 1 and y1, respectivel At the prompt, enter the following and press ENTER. x1:=x+0.05 y1:=y+0.05 The names x and y have values assigned to them. Since x and y are used variables in future calculations, they must be unassigned before proceeding To unassign x and y At the prompt, enter the following and press ENTER. y:=y;2.3 Math and Visualization • 13 To find the partial derivative of  with respect to : • At the prompt, enter the following and press ENTER. "%&'"""%$ Since you are interested in the real solution, use the "
/ command instead of the more general
/ command. To solve the system of equations    : • At the prompt, enter the following and press ENTER. 0%&'"
/1"'"%'21%21'3( %'3( 2$ The top of the hill is therefore at approximately 1'− 4,5))44 %'3) 67,,-2. Note: Sets do not preserve order, so you may instead obtain the equivalent set: { %'−) 67,,-' − 4,5))442. Finding the skier’s starting point Assume that the skier does not start at the peak but slightly to the side. To approximate this location, add a small factor, say  7, to the 3 and %3 values. Assign these values to the variables  and % and then add the approximating factor. To assign the values to the variables: • At the prompt, enter the following and press ENTER. 

8$ The ditto operator (%) refers to the result of the previous computation. For more information, refer to 8 (The ditto operators). To define the starting 3 and %3values, )and%), respectively: • At the prompt, enter the following and press ENTER. )&'* 7$ %)&'%* 7$ The names  and % have values assigned to them. Since  and %are used as variables in future calculations, they must be unassigned before proceeding. To unassign  and %: • At the prompt, enter the following and press ENTER. &'99$ %&'9%9$