Verify associativity for the following three mappings: f: N → Z0 (the set of non – zero integers), g: Z0→ Q and h: Q → R given by f(x) = 2x, g(x) = 1/x and h(x) = ex.
We have, f: N → Zo, g: Z0 → Q and h: Q → R
Also, f(x) = 2x, and h(x) = ex
Now, f: N → Zo and hog: Z0 → R
∴ (hog)of: N → R
Also, gof: N → Q and h: Q → R
∴ ho(gof): N → R
Thus, (hog)of and ho(gof) exist and are function from N to set R.
Finally. (hog)of(x) = (hog)(f(x)) = (hog)(2x)
Now, ho(gof)(x) = ho(g(2x)) = h
Hence, associativity verified.