(f∘g)(x) means f(g(x)) which means we substitute what g(x)
equals for x in the right side of f(x) if x appears in the right
side of f(x). If f(x) is a constant, it stays constant no matter
what x is.
on the interval where x < 0 f(x) is a constant function so
regardless of what g(x) is there, f(x) will be constantly 1.
So the first part of (f∘g)(x) is (f∘g)(x) = 1 if x < 0
On the interval where
, g(x) is 3x, so we substitute 3x
for x in that part of f(x), which is 2x² and get 2(3x)² or 2(9x²) or 18x².
So the second part of (f∘g)(x) is (f∘g)(x) = 18x² if
on the interval where x > 1, f(x) is a constant function so
regardless of what g(x) is there, f(x) will be constantly 1.
So the third part of (f∘g)(x) is (f∘g)(x) = 1 if x > 1.
Therefore:
Edwin