How can I solve this question?

I am very confusion about this question

Forget about face recognition, James. The latest SPECTRE internet password requires you to combine functions in the innite dimensional vector space of functions to obtain a \"O-key" to crack into their evil web-portal. The pass key app here shows the functions ex .e'x, cosh x, and sinhx together with the linear key combination f(x) = ae" + bex + ccoshx +d sinhx. Your mission, if you choose to accept it, is to nd some combination of coefficients that will: i) ensure that the function f(Jc) = aux +be_x + ccoshx+ d sinhx is the zero function (or at least very close to it), and ii) at least one of a, b, c, d is exactly equal to 1. Your solution James? Clearly the answer, or at least one answer, M, is given by the vector at b c d