Let f1(x) and f2(x) be functions from the set of real numbers to the set of positive real numbers. Show that if f1(x) and f2(x) are both ? (g(x)), where g(x) is a function from the set of real numbers to the set of positive real numbers, then f1(x) + f2(x) is ?(g(x)). Is this still true if f1 (x) and f2(x) can take negative values?

Solution:Step 1:The objective of this question, is this still true if f1 (x) and f2(x) can take negative valuesStep 2:Given that:f1 , f2 and g are the functions from R to R+And f1 f2 Such that k and C1 , C2 , > 0 Whenever x >kAccording to the question, f1 , f2 and g are all the positive real number whenever x> k