Here you go:
Let f(x) = x2 + 2x and let g(x) = √(2x-1).
By definition of function composition:
f compose g, otherwise known as f°g is defined as follows: f°g = f(g(x)).
Similarly, g°f = g(f(x)).
When we write out f(g(x)), for every x within the equation f(x) = x2 + 2x, we substitute √(2x-1) in for every x, as follows:
Noting that f(x) = x2 + 2x and g(x) = √(2x-1)
f°g = f(g(x)) = (√(2x-1))2 + 2(√(2x-1))
Also: g°f = g(f(x)) = √(2(x2 + 2x) -1)
For Part 2, when we write out f+g, this is written as f(x) + g(x) and done by simply adding the two functions, as follows:
f + g = f(x) + g(x) = (x2 + 2x) + √(2x-1) .
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