Homework matlab problem - Determine r1, r2 and surface area - use matrix?

Question

Morley 2011-9-28

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评论： Walter Roberson 2021-10-27

ive been staring at this problem and cant get anything. im a college student i dont u see what to do with the unknown variables

the unit we are in now is covering - input and output commands - display commands - fprintf - load commands

help will be greatly appreciated KEEP IT SIMPLE IF POSSIBLE. THIS IS ONLY CHAPTER 4 OF AN INTRO CLASS

an ice cream cone shaped as a frustum of a cone with R2=(1.2)(R1) is designed to have a volume of 1,000 cm cubed. Determine R1, R2 and the surface area , s, of the paper for containers with heights h of 8, 10, 12, 14, and 16 cm. Display the results in a table. The volume of the container, V, and the surface area of the paper are given by

V = (1/3)(pi)(h)(R1^2 + R2^2 + R1R2)

S = (pi)(R1+R2)sqrt[(R2-R1)^2 + h^2] + (pi)(R1^2 + R2^2)

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Morley 2011-9-28

i understand that it seems i have not put much effort into this problem, but it is 2:30am here and ive got class at 8. i really am trying. my problem is i dont know what to do with the unknown variables so i dont know where to start. the unit we are in now is covering

- input and output commands

- display commands

- fprintf

- load commands

M VENKATESH 2021-9-10

A cone shaped cup is designed to have a volume of 250 cm³. Determine the radius, r, of the base and the surface area, S, of the paper for cups with heights, h of 5,6,7,8, and 9 cm. The volume V, and the surface are of the paper are given by: V=1/2pi r²h und S = pi r sqrt(r²+h²). How to put this problem

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Answer 1

UJJWAL 2011-9-28

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在 MATLAB Online 中打开

Hi Morley.

Below Is a code that solves your problem. Go through each step and understand. I hope it will help. For further details mail back

R1 = sym('R1','positive'); % Define R1 as a symbolic variable . It is positive
R2 = 1.2* R1; % Mention the relation between R1 and R2
table = zeros(5,4); % The table stores the h in the first column . The second column stores R1, the third one stores R2 and the fourth one stores s
table(:,1)=8:2:16; % Store the heights
for i = 1:5
    x= solve((1/3)*pi*table(i,1)*(R1.^2 + R2.^2 + R1*R2)- 1000,'R1'); %Solve for the values of R1
    table(i,2) = x; 
    table(i,3) = 1.2*x;
    table(i,4) = pi * (1.3*x) *sqrt((0.2*x)^2 + table(i,1)^2) + pi*(x^2 + (1.2*x)^2); % Calcualte the surface area
end

Hope This helps

HAPPY TO HELP

UJJWAL

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Answer 2

Andrei Bobrov 2011-9-28

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在 MATLAB Online 中打开

EDITED

syms R1 R2 h  S positive
r1s = subs([1000 - 1/3*pi*h*(R1^2 + R2^2 + R1*R2),...
        pi*(R1+R2)*sqrt((R2-R1)^2 + h^2) + pi*(R1^2 + R2^2)],R2,1.2*R1)
r1s(1) = solve(r1s(1),R1)
f = cell(2,1); for j1 = 1:2, f{j1} = matlabFunction(r1s(j1)); end
h = (8:2:16)';
r1 = f{1}(h);
out = [h,r1,1.2*r1,f{2}(r1,h)]

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Amin Sultan 2019-2-26

How would you arrange the values into columns

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Answer 3

Jackie Cortez 2016-10-18

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Is there a way to do this problem without using syms or subs? It keeps telling me I have to License and install the Symbolic Math Toolbox which I don't have.

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Andrei Bobrov 2019-2-26

在 MATLAB Online 中打开

Without Symbolic Math Toolbox:

Veq1000 = @(h,R1)1000 - 1357/356*h.*R1.^2;
s = @(h,R1)(R1*pi.*(61*R1 + 11*(R1.^2 + 25*h.^2).^(1/2)))/25;
h = (8:2:16)';
n = numel(h);
r1 = zeros(n,1);
for ii = 1:n
    r1(ii) = fzero(@(R1)Veq1000(h(ii),R1),1);
end
out = [h,r1,1.2*r1,s(h,r1)];

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Answer 4

Divya Pateriya 2019-10-17

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在 MATLAB Online 中打开

h = input('Please enter the array of height :');
v=input('please tell the volume of frustum :');
r1 = sqrt((3*v)./(pi*h.*3.64));
r2=(1.2).*r1;
s=pi.*(r1+r2).*sqrt((r2-r1).^2+h.^2)+pi.*(r1.^2+r2.*2);
Result=[h;r1;r2;s];
Table = Result'

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John D'Errico 2019-10-17

编辑：John D'Errico 2019-10-17

Sigh. This does not display the result in a table. It creates a variable named Table. It only computes the result for ONE value of h, so there is no table created anyway.

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Answer 5

dania tr 2021-10-27

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The surface area A of a sphere depends on its radius r as follows: A = 4 ᴫ r 2 . Write a MATLAB function to compute the surface area. Call your function to compute A at r = 5 and display the result.