(* CALCULUS 265 Honors Fall Semester 2000 8:00 to 8:50 MTTF Carver 0002 Instructor: Hentzel Office: 432 Carver Office Hours: 9:00-10:00 MTTF E-mail hentzel@iastate.edu phone 294-8141 Website http://www.math.iastate.edu/hentzel/honors.265 <##### NEW ADDRESS #### Thursday, September 28: Review. 1. Find the volume above z = x^2+y^2 which is below the plane z = 4; Integrate[ r,{t,0,2 Pi},{r,0,2},{z,r^2,4}]; ans = 8 Pi. 2. Find the surface area of the surface z = x^2 + y^2 below the plane z = 4. Integrate[ r Sqrt[1+ 4 r^2],{t,0,2 Pi},{r,0,2}] (-1 + 17 Sqrt[17]) Pi ans = --------------------- 6 3. Convert the following into Cylindrical coordinates. Do not integrate. 2 +Sqrt[4-x^2] Sqrt[16-x^2-y^2] INT INT INT Sqrt[x^2+y^2] dzdydx. 0 -Sqrt[4-x^2] 0 Mathematica would only integrate the original problem numerically giving 30.8723 Integrate[r^2,{t,-Pi/2,Pi/2},{r,0,2},{z,0,Sqrt[16-r^2]}] 16 Pi Out[7]= Pi (-4 Sqrt[3] + -----) 3 4. Convert the following into Spherical coordinates. Do not integrate. 1 Sqrt[1-x^2] Sqrt[1-x^2-y^2] INT INT INT Sqrt[x^2+y^2+z^2] dz dy dx 0 0 0 Integrate[Sqrt[x^2+y^2+z^2],{x,0,1},{y,0,Sqrt[1-x^2]},{z,0,Sqrt[1-x^2-y^2]}] Numerically integrating gives 0.392699. Integrate[p^3 Sin[f],{t, 0,Pi/2},{f,0,Pi/2},{p,0,1}] Pi Out[1]= -- 8 5. Set up the Integral for the moment about the xy plane of the portion of the cone z = Sqrt[x^2 + y^2] below z = h in Spherical coordinates. Integrate[p^3 Sin[f] Cos[f],{t,0,2 Pi},{f,0,Pi/4},{p,0,h Sec[f]}]; 4 h Pi Out[2]= ----- 4 6. Set up the Integral for the volume of the portion of the sphere x^2+y^2+z^2 = a^2 above z = b in cylindrical coordinates. Integrate[r,{t,0,2 Pi},{r,0, Sqrt[a^2-b^2]},{z,b,Sqrt[a^2-r^2]}] 2 3/2 2 3/2 2 (a ) Pi 2 3 2 (b ) Pi Out[1]= ------------ - a b Pi + b Pi - ------------ 3 3 7. Set up the Integral for the surface area of the portion of the sphere x^2 + y^2 + z^2 = a^2 above z = b using polar coordinates. Integrate[a r/Sqrt[a^2 - r^2],{t,0,2 Pi},{r,0,Sqrt[a^2-b^2]}] 2 2 Out[1]= 2 (a Sqrt[a ] - a Sqrt[b ]) Pi 8. Set up the integral for Iz for the sno-cone which is the intersection of the Sphere x^2 + y^2 + z^2 = a^2 and the cone z^2 = 2(x^2 + y^2) in spherical coordinates. Integrate[p^4 Sin[f]^3,{t,0,2 Pi},{f,0,ArcTan[1/Sqrt[2]]},{p,0,a}] 5 1 5 a (-3 Sqrt[6] + Cos[3 ArcTan[-------]]) 2 a Sqrt[2] Out[1]= 2 Pi (---- + ----------------------------------------) 15 60 In[2]:= N[%] 5 Out[2]= 0.039727 a 9. Set the integral for the volume inside the sphere x^2+y^2+z^2 = a^2 and above z = x^2 + y^2 in Cylindrical coordinates. 10. Give a geometrical interpretation of the triple integral. 2 Pi Pi 6 Sin[phi] INT INT INT p^2 Sin[f] d(rho) d(phi) d(theta) 0 0 0