果fx10，则x1即为所求根，否则选取x1fx1点和点afa（该点的选取要满足条件fa与fx同号，并改记为x0fx0。再做弦此弦与轴交点的横坐标设为x2依次类推，其迭代格式即为xk1xkfxkxkx0fxkfx0双点弦截法无固定点xk1xkfxkxkxk1fxkfxk1formatlo
g
x
x15
x2
x12
x1
x1212
x1log22
x1k1whileabs
xk1
xk106kk1
xk1
xk2
xk
xk212
xklog22
xke
d
kk1disp牛顿迭代法迭代次数：
um2str
kbla
ks4方程的解：
um2str
x
kdxdx15dx2dx12dx1dx121233212552135k1whileabsdxk1dxk106kk1dxk1dxk2dxkdxk212dxkdxk2125521dxk5e
ddisp单点迭代法迭代次数：
um2strkbla
ks4方程的解：
um2strdxksxsx15sx23k1whileabssxk1sxk0000001kk1sxk1sxk2sxksxk212sxksxk212sxk1sxk121sxksxk1e
d
fskk1disp双点迭代法迭代次数：
um2strskbla
ks4方程的解：
um2strsxskx30055y2xx21y
zeros1
kydzeros1sksubplot121plotxysxydtitle双点弦截法gtexty2xx21subplot122plotxy
xy
title牛顿迭代法gtexty2xx21
二分法fu
ctio
approx_rootbisectabtolfabifu
afbbifu
bwhileabsbatolcab2approx_rootcfcbifu
cacbfafcfbifsig
fbsig
fc0acfafcelsebcfbfce
de
dfu
ctio
fbifu
xfx3si
x输入你的方程f（x）0ab为区间a40b46牛顿法x046
为迭代上限，tol为精度fu
ctio
y
ewto
1x0
tolx1x0b1
fi1AixiBibCi1whileabsbepsxixi1xifu
1xidfu
1xibxi1xiii1AixiBibCifevalfu
1xiifi
error
isfulle
de
dyxiACBfu
ctio
yfu
1xyx2si
xfu
ctio
fdfu
1xsymsxfdoubledifffu
1x
solve1x3cos40xsi
40x2si
h40x1x3cos40xcosh40x1x3si
40x1x3si
h40xcos40xcosh40x1x3si
h40xsi
40x1x3cosh40xsi
h40x2si
40x1x3cos40xcosh40x0symsxfi
li
e1x3cos40xsi
40x2si
h40x1x3cos40xcosh40x1x3si
40x1x3si
h40xcos40xcosh40x1x3si
h40xsi
40x1x3cosh40xsi
h40x2si
40x1x3cos40xcosh40xxx02xfvfsolvefx0optimsetTolFu
1e16
fx1x3cos40xsi
40x2si
h40x1x3cos40xcosh40x1x3si
40x1x3si
h40xcos40xcosh40x1x3si
h4
f0xsi
40x1x3cosh40xsi
h40x2si
40x1x3cos40xcosh40xxfsolr