to prove that 6720. Sin 40. Sin 60. 80 equals 3 you'd have to divide 16 by 20 multiply subtract both sides by 3 which is 24x + 6x + 8x + -14 equals 40 40 + 20 equals 16 - -40 equals 80 which equals to 3
I think that the best answer is A
(f∘g)(x) = f(g(x)) = f(x +2)
= 2(x +2) -1
= 2x +3 . . . . . selection D
Note that f(x) as given is <em>not</em> invertible. By definition of inverse function,


which is a cubic polynomial in
with three distinct roots, so we could have three possible inverses, each valid over a subset of the domain of f(x).
Choose one of these inverses by restricting the domain of f(x) accordingly. Since a polynomial is monotonic between its extrema, we can determine where f(x) has its critical/turning points, then split the real line at these points.
f'(x) = 3x² - 1 = 0 ⇒ x = ±1/√3
So, we have three subsets over which f(x) can be considered invertible.
• (-∞, -1/√3)
• (-1/√3, 1/√3)
• (1/√3, ∞)
By the inverse function theorem,

where f(a) = b.
Solve f(x) = 2 for x :
x³ - x + 2 = 2
x³ - x = 0
x (x² - 1) = 0
x (x - 1) (x + 1) = 0
x = 0 or x = 1 or x = -1
Then
can be one of
• 1/f'(-1) = 1/2, if we restrict to (-∞, -1/√3);
• 1/f'(0) = -1, if we restrict to (-1/√3, 1/√3); or
• 1/f'(1) = 1/2, if we restrict to (1/√3, ∞)
43 47 53 59 are the prime numbers