fsolve does not work when combining functions

i have the following functions:

f1 = @(k1)108.4*k1

f2 = @(k2)108.4*k2

f3 = @(k3)108.4*k3

f1,f2,f3 are automatically generated, and can be very different. i would like to have a unifying function

f = f1 + f2 + f3

and i want to call f in solvers such as fsolve or fmincon. these are some suggestions i recieved:

    sumf = @(k1,k2,k3) f1(k1)+f2(k2)+f3(k3);

    sumf( 1, 2, 3 )
    ans =
      650.4000

or

    sumf = @(k) f1(k)+f2(k)+f3(k);

    sumf( 2 )
    ans =
      650.4000

but fsolve does not accept

sumf = @(k1,k2,k3) f1(k1)+f2(k2)+f3(k3);

fsolve takes the function in the form

sumf = @(k) f1(k(1))+f2(k(2))+f3(k(3));

is there any way to combine them so that they can be put into fsolve ?

Answer 1

[Matt Fig]

Why won't this work?

sumf = @(k) f1(k(1))+f2(k(2))+f3(k(3));
sumf([1 2 3].')
fsolve(sumf,[3;1;2])