Trouble superimposing two functions onto the same graph. One is correct, the other is incorrect.

% I am trying to plot the functions y1 and y2. Both functions should start at 0,1. Whenever I graph it though, the % y1 starts properly, whereas the y2 starts below the x axis. I'm not sure why, and any help would be appreciated

% Y1 is the original function

% Y2 is the derivativef of Y1

%% Define x variables

x = linspace(0,pi,200);

%% calculate y values

y1 = atanCos1(x); %function (can be found below)

y2 = d_atanCos1(x);%function (can be found below)

%% Part C: plot the atanCos1 and d_atanCos1 curve

figure

hold on

plot(x,y1,'b-')

plot(x,y2,'g-')

%% FUNCTIONS WRITTEN BELOW written in seprate .m files

--------------------------

function[y1] = atanCos1(x)

y1 = (atan(x).*cos(x)) + 1;

end

--------------------------

function[y2] = d_atanCos1(x)

y2 = cos(x)/(x.^2 + 1) - atan(x).*sin(x);

end

%% here is the graph below

Answer 1

[Torsten]

y2 = cos(x)./(x.^2 + 1) - atan(x).*sin(x);

instead of

y2 = cos(x)/(x.^2 + 1) - atan(x).*sin(x);

%% Define x variables
x = linspace(0,pi,200);
%% calculate y values
y1 = atanCos1(x);  %function (can be found below)
y2 = d_atanCos1(x);%function (can be found below)
%% Part C: plot the atanCos1 and d_atanCos1 curve
hold on
plot(x,y1,'b-')
plot(x,y2,'g-')
hold off
grid on

function [y1] = atanCos1(x)
  y1 = (atan(x).*cos(x)) + 1;
end

function [y2] = d_atanCos1(x)
  y2 = cos(x)./(x.^2 + 1) - atan(x).*sin(x);
end

[Allan]

Thank you so much for your help and quick response!!