# Homework # 7 # Selected Answers # > restart: # Question 1: > f:=4*x^3*y^2+3*x^2*y^4-7*x*y^2+4*x-3*y+2; > fx=diff(f,x); > fy=diff(f,y); # Question 2: > f:=x^3*exp(2*y)+y^2*ln(3*x); > fx=diff(f,x); > fy=diff(f,y); # Question 3: > f:=(5*x*y^2)/(x^3+y^3); > fx=diff(f,x); > fy=diff(f,y); # Question 4: > f:=4*y^3/(x^3+y^2); > fx=diff(f,x); > fy=diff(f,y); # Question 5: > f:=x^2*sqrt(y^2+z); > fx=diff(f,x); > fy=diff(f,y); > fz=diff(f,z); # Question 6: > f:=x^2*y*z^2+x*y^2*z+x*y; > fx:=diff(f,x); > fx_solution=subs({x=1,y=2,z=3},fx); # Question 7 > z:=exp(x/y); > fy=diff(z,y); # Question 8: > Q:=sqrt((2*C*M)/s); > Qc:=diff(Q,C); > solution=subs({C=100,M=500,s=3},Qc); > evalf(%); # Question 9: > c:=0.002*(x+y)^2+x+0.25*y+8000; > Cx:=diff(c,x); > subs({x=450,y=550},Cx); > restart: # Question 10 > p:=2.1*L^(0.6)*K^(0.4); > MP_labour:=diff(p,L); > MP_capital:=diff(p,K); >