help with numerical analysis
2 views (last 30 days)
Show older comments
if true
fplot('pi*x*sqrt((x)^2+((750/pi)^2)/(x)^4)',[0,10]);
[R fmin]=fminbnd('pi*x*sqrt((x)^2+((750/pi)^2)/(x)^4)',0,8);
h=170/(pi*R^2);
grid on
fprintf('The Value of R is %5.4f cm and the Height is %5.4f cm\n',R,h)
end
a paper cup shaped as a cone is designed to have a volume of 250cm^3. Determine the radius R and height h such that the least amount of paper will be used for making cup my answers came up as
Value of R is 5.5267 cm and the Height is 1.7716 cm but the book says is Value of R is 6.9632cm and the height is 4.9237 any advice or any mistakes that you can point out, thanks
0 Comments
Accepted Answer
Andrei Bobrov
on 24 Jul 2013
Edited: Andrei Bobrov
on 24 Jul 2013
syms R H V real
H = 3*V/(pi*R^2);
S = subs(pi*R*sqrt( R^2/4+H^2 ),V,250);
Rout = double(solve(diff(S,R),R));
Rout = Rout(Rout>0&imag(Rout)==0)
Hout = double(subs(H,{V,R},{250,Rout}))
OR
[R fmin]=fminbnd(@(x)pi*x.*sqrt(x.^2/4+(750/pi)^2./x.^4),0,8)
More Answers (1)
Raghavendra
on 24 Jul 2013
Basically the equation for cone says Volume(V)= (Pi*r*r*h)/3; You have two unknown variable, Lets assume the radius = 2, then you can use this formula to find out the Height.
0 Comments
See Also
Categories
Find more on Polynomials in Help Center and File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!