Problem 1031. Composite Trapezoidal Rule for Numeric Integration

Solution 369233

Submitted on 12 Dec 2013 by Michael Frietsch

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Test	Status	Code Input and Output
1	Pass	%% Simple Trapezoidal Rule p=[2 0 -4 0 -1 1]; a=-2; b=4; f = @(x) polyval(p,x); assert(isequal(trapezoidal_rule(f,a,b,1),5280))
2	Pass	%% Composite Trapezoidal Rule for 2 intervals p=[2 0 -4 0 -1 1]; a=-2; b=4; f = @(x) polyval(p,x); assert(isequal(trapezoidal_rule(f,a,b,2),2634))
3	Pass	%% Composite Trapezoidal Rule for 4 intervals p=[2 0 -4 0 -1 1]; a=-2; b=4; f = @(x) polyval(p,x); assert(isequal(trapezoidal_rule(f,a,b,4),1516.875))
4	Pass	%% Exact analytical comparison p=[2 0 -4 0 -1 1]; a=-2; b=4; f = @(x) polyval(p,x); P=polyint(p); I_correct=polyval(P,b)-polyval(P,a); I=trapezoidal_rule(f,a,b); assert(abs(I-I_correct)<1)
5	Pass	%% Exact analytical comparison--higher tolerance p=[2 0 -4 0 -1 1]; a=-2; b=4; f = @(x) polyval(p,x); I = trapezoidal_rule(f,a,b,1000); P=polyint(p); I_correct=polyval(P,b)-polyval(P,a); assert(abs(trapezoidal_rule(f,a,b,1000)-I_correct)<1e-1)