About the only thing you might want to change is to put a call in to the HOLD function so that all plots appear on the same axis, or pass all the arguments to plot at once. Like this:
function [sinh1x,cosh1x,tanh1x] = hyper(X)
sinh1x = sinh(X);
cosh1x = cosh(X);
tanh1x = tanh(X);
plot(X,sinh1x,X,cosh1x,X,tanh1x)
legend({'sinh(x)';'cosh(x)';'tanh(x)'},'location','northwest')
grid on
Then call it like this:
>> [sinh1x,cosh1x,tanh1x] = hyper(0:.01:1);
