實驗二matlab實驗報告

實驗序號 日期 年11 19計算，Matlab有專門函數(shù)可用。矩形法．但是，只有當(dāng)積分區(qū)間被分割得很細(xì)時，矩形法才有一定的精確度．針對不同的取法，有三種辦法：左點法、右點法、中點法，不同的辦法計算成果會有不同。

，即，sum(a)aformatlong15（注：由于本實驗要比較近似解法和精確求解間的誤差，需要更高的精度double()ASCII碼；若輸入的是整型數(shù)值則轉(zhuǎn)化為對應(yīng)的實型數(shù)quad()quad(fun,a,b)fun是函數(shù)，并且為數(shù)值形式的，因此使用*、/、^等運算時要在其前加上小數(shù)點，即.*、./、.^等．x為帶有步長的積分區(qū)間；y為數(shù)值形式的運算（dblquad()格式：dblquad(fun,xmin,xmax,ymin,ymax)，funinline定義，也能夠通過某個函數(shù)文獻(xiàn)的句柄fprintf（文獻(xiàn)地址，格式，寫入的變量）：subs(f，'x'，a)afxsubs(f)syms12重要內(nèi)容（要點 ．并嘗試直接使用函數(shù)trapz()、quad()進(jìn)行計算試計算定積 （fulu2sum.msum13forformatlongsymsxfxfori=1:nfprintf('Therelativeerrorbetweeninumandreal_valueisabout:%g\n\n',abs((inum-trapz(x,fx))/trapz(x,fx)))辦法二：（拋物線法formatlongsymsxfxfori=1:n about:%g\n\n',abs((inum-quad('1./x',1,2))/quad('1./x',1,2)))辦法一（辦法二（formatlongsymsxfxfori=1:nfprintf('Therelativeerrorbetweeninum1andreal-valueisabout:%g\n\n',...fprintf('Therelativeerrorbetweeninum2andreal-valueisabout:%g\n\n',...fprintf('Therelativeerrorbetweeninum3andreal-valueisabout:%g\n\n',...formatlongsymsxfxf1=(fxi)*(b-fprintf('Therelativeerrorbetweeninumandreal_valueisabout:%g\n\n',abs((inum-辦法二（sum函數(shù)——拋物線法formatlongsymsxfxquad('1./x',1,2,1e- about:%g\n\n',abs((inum-quad('1./x',1,2,1e-16))/quad('1./x',1,2,1e-16)))辦法三（sum函數(shù)——梯形法）formatlongsymsxfxfprintf('Therelativeerrorbetweeninumandreal_valueisabout:%g\n\n',abs((inum-fulu2sum.m的程序設(shè)計辦法。于是學(xué)1/2*pi。2bbinfb改為較大的1001000來替代無窮大，即得到成果。但誤差較大，錯誤成果為：inumintegrate=Therelativeerrorbetweeninum1andreal-valueisabout:boinumfTherelativeerrorbetweeninumandreal_valueisabout:0inumans3辦法（1）ans辦法（2）ans辦法（3）inumintegrate=Therelativeerrorbetweeninum1andreal-valueisabout:2.38752e-Therelativeerrorbetweeninumandreal_valueisabout:2.78348e-0083辦法一inumfTherelativeerrorbetweeninumandreal_valueisaboutinumansTherelativeerrorbetweeninumandreal_valueisabout:1.35886e-inum1inum2inum3fTherelativeerrorbetweeninumandreal_valueisabout:0Therelativeerrorbetweeninumandreal_valueisaboutTherelativeerrorbetweeninumandreal_valueisa