I do not know how to solve with this question..

Please give me an explanation

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