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gibson:teaching:fall-2012:math445:pf1-solns

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gibson:teaching:fall-2012:math445:pf1-solns [2012/12/11 14:19]
gibson
gibson:teaching:fall-2012:math445:pf1-solns [2012/12/11 14:22] (current)
gibson
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 </​latex>​ </​latex>​
  
-So $dx/dt = [x_2, -g - \mu x_2 |x_2|]$+So $dx/dt = [x_2, ~-g - \mu x_2 |x_2|]$
  
  
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 from the initial conditions $x(0) = [y(0), ~v_y(0)] = [0, 0]$. from the initial conditions $x(0) = [y(0), ~v_y(0)] = [0, 0]$.
  
 +<​code>​
   g  = 9.81;   g  = 9.81;
   mu = 0.35;      mu = 0.35;   
   f = @(x) [x(2) ; -g - mu*x(2)*abs(x(2)];​   f = @(x) [x(2) ; -g - mu*x(2)*abs(x(2)];​
  
-  [t, x] = ode45(f, 0:100, [0 ; 0]); +  [t, X] = ode45(f, 0:100, [0 ; 0]); 
 +</​code>​
  
  
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 Label the axes.  Label the axes. 
  
-  plot(t, ​x(:,1)) % first column of is 1st component of x as a function of time+  plot(t, ​X(:,1)) % first column of returned X is 1st component of x as a function of time
   xlabel('​t'​)   xlabel('​t'​)
   ylabel('​y = height of ball')   ylabel('​y = height of ball')
Line 277: Line 278:
 of A.  of A. 
  
 +<​code>​
   function y = sparse_matvec_mult(A,​x)   function y = sparse_matvec_mult(A,​x)
     K = nnz(A);     K = nnz(A);
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     end     end
   end   end
 +</​code>​
gibson/teaching/fall-2012/math445/pf1-solns.1355264399.txt.gz · Last modified: 2012/12/11 14:19 by gibson