Re: [討論]方程式求解(特定輸入範圍)

[zupo (朝著目標前進)]

※ 引述《jim84jim84 (Weiso)》之銘言：
: 如果fun(x)=abs(abs(abs(x)-5)-2) 而x的範圍:-5~7
: 若fun(x)=1 則我知道x的答案為-4,-2,-6
: 但我要如何以MATLAB實現上述的想法?
: 因為在網路上查到的function 像fsolve,solve好像只會傳回一個輸出
: 謝謝

  本題需要先畫出圖形後觀察零解起猜值

-----------------------------------------
function pttex147
x = -5:0.01:7;
x = x';
y = abs(abs(abs(x)-5)-2);
plot(x,y,x,y,'o')
Zerosolu = zeros(3,1);
% 由上圖可看到變更零解起猜值的大約範圍
x0 =[-4;2;6]
Zerosolu(1) = fsolve(@obj,x0(1));
Zerosolu(2) = fsolve(@obj,x0(2));
Zerosolu(3) = fsolve(@obj,x0(3));
Zerosolu

function f = obj(x)
f = abs(abs(abs(x)-5)-2);
-----------------------------------------


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