南郵數(shù)學(xué)實(shí)驗(yàn)答案

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1、第一次練習(xí)題1、求的所有根。>>x=-5:0.01:5;y=exp(x)-3*x.^2;plot(x,y);gridon>>fsolve('exp(x)-3*x.^2',-1)Equationsolved.fsolvecompletedbecausethevectoroffunctionvaluesisnearzeroasmeasuredbythedefaultvalueofthefunctiontolerance,andtheproblemappearsregularasmeasuredbythegradient.

2、iadetails>ans=-0.4590>>fsolve('exp(x)-3*x.^2',1)Equationsolved.fsolvecompletedbecausethevectoroffunctionvaluesisnearzeroasmeasuredbythedefaultvalueofthefunctiontolerance,andtheproblemappearsregularasmeasuredbythegradient.ans=0.9100>>fsolve('exp(x)-3*x

3、.^2',4)Equationsolved.fsolvecompletedbecausethevectoroffunctionvaluesisnearzeroasmeasuredbythedefaultvalueofthefunctiontolerance,andtheproblemappearsregularasmeasuredbythegradient.ans=3.73312、求下列方程的根。1)2）3）1)>>p=[1,0,0,0,5,1];r=roots(p)r=1.1045+1.0598

4、i1.1045-1.0598i-1.0045+1.0609i-1.0045-1.0609i-0.19992)>>x=-10:0.01:10;y=x.*sin(x)-1/2;plot(x,y);gridon>>fsolve('x.*sin(x)-1/2',-6)Equationsolved.fsolvecompletedbecausethevectoroffunctionvaluesisnearzeroasmeasuredbythedefaultvalueofthefunctiontolerance,andtheproblemappearsregu

5、larasmeasuredbythegradient.ans=-6.3619>>fsolve('x.*sin(x)-1/2',-4)Equationsolved.fsolvecompletedbecausethevectoroffunctionvaluesisnearzeroasmeasuredbythedefaultvalueofthefunctiontolerance,andtheproblemappearsregularasmeasuredbythegradient.

6、teriadetails>ans=-2.9726>>fsolve('x.*sin(x)-1/2',2)Equationsolved.fsolvecompletedbecausethevectoroffunctionvaluesisnearzeroasmeasuredbythedefaultvalueofthefunctiontolerance,andtheproblemappearsregularasmeasuredbythegradient.ans=0.74083)>>x=-3:0.01:3;y

7、=sin(x).*cos(x)-x.^2;plot(x,y);gridon>>fsolve('sin(x).*cos(x)-x.^2',-1)Equationsolved.fsolvecompletedbecausethevectoroffunctionvaluesisnearzeroasmeasuredbythedefaultvalueofthefunctiontolerance,andtheproblemappearsregularasmeasuredbythegradient.ans=-6.

8、8434e-010>>fsolve('sin(x).*cos(x)-x.^2',1)Equationsolved.fsolvecompl