如何用matlab解方程2^x-x-1=0

参见doc solve Return Numeric Solutions Solve the following equation: syms x solve(sin(x) == x^2 - 1)The symbolic solver cannot find an exact symbolic solution for this equation, and therefore, it calls the numeric solver. Because the equation is not polynomial, an attempt to find all possible solutions can take a long time. The numeric solver does not try to find all numeric solutions for this equation. Instead, it returns only the first solution that it finds:ans = -0.63673265080528201088799090383828 以上，它说它只找第一个解 Plotting the left and the right sides of the equation in one graph shows that the equation also has a positive solution: ezplot(sin(x), -2, 2) hold on ezplot(x^2 - 1, -2, 2) hold off You can find this solution by calling the MuPAD(R) numeric solver directly and specifying the interval where this solution can be found. To call MuPAD commands from the MATLAB(R) Command Window, use the evalin or feval function:evalin(symengine, 'numeric::solve(sin(x) = x^2 - 1, x = 0..2)')ans = 1.4096240040025962492355939705895 然后它说可以画个图，大概看看另一个解在哪，然后用它内置的方法来求解，并且给个参数告诉它求解的区间 针对你的问题，另一个解这样求： evalin(symengine, 'numeric::solve(2^x-x-1=0, x = 0.1..2)') 可得： ans = 1.0