write code to solve trigonometric equation

Hello !

I am a begineer to matlab and i need to solve this trignometric equation using matlab graphically, could anyone help

func : cosh x cos x + 1

I tried to write the following code but it didn't work anymore

p= @(x) (cosh(x)*cos(x)+1);
x=[-2*pi:0.1:2*pi];
plot (x,p(x));

i tried to plot this equation with the given intervial but this message was shown "nonconformant arguments (op1 is 1x126, op2 is 1x126)

error: called from"

thanks

Answer 1

[VBBV]

p= @(x) (cosh(x).*cos(x)+1);
x=[-2*pi:0.1:2*pi];
plot(x,p(x));

[Ahmed]

thanks so much !, how to catch the x-roots from the graph ?

[Walter Roberson]

p= @(x) (cosh(x).*cos(x)+1);
x=[-2*pi:0.1:2*pi];
px = p(x);
plot(x,px);

mask = find(px(1:end-1) .* px(2:end) <= 0);
[x(mask).', px(mask).', px(mask+1).']

ans = 4×3

-4.7832 5.2263 -0.5786 -1.8832 -0.0336 0.3553 1.8168 0.2310 -0.1779 4.6168 -3.8278 1.2474

[Ahmed]

excellent! thanks for your answer!