sum two functions together

Hi,

I wanna sum two (or more) functions together, like image below.

What efficient way do you recommend?

Thank you.

[KSSV]

USe Sum.

[Amir]

Each function define in its domain!

First function: from a to d,

Second function: from c to f,

Third function: from b to e.

[Torsten]

fun1 = @(x)...;
fun2 = @(x)...;
fun3 = @(x)...;
fun_sum = @(x) fun1(x) + fun2(x) + fun3(x);

[Amir]

Thank you Torsten, It worked well.