Step-by-step explanation:
the derivative of an inverse function is
1/f'(f^-1(x))
f'(x) = -6x²
f^-1(7) is solving the original function equation for x under the knowledge that y = 7
7 = 5 - 2x³
2 = -2x³
-1 = x³
=>
x = -1
f'(-1) = -6×(-1)² = -6×1 = -6
so,
(f^-1)'(7) = -1/6
Answer:
115
Step-by-step explanation:
There is a common difference d between consecutive terms, that is
d = 7 - 1 = 13 - 7 = 19 - 13 = 25 - 19 = 6
This indicates the sequence is arithmetic with n th term
= a₁ + (n - 1)d
where a₁ is the first term and d the common difference
Here a₁ = 1 and d = 6 , thus
a₂₀ = 1 + (19 × 6) = 1 + 114 = 115
The answer is Lucy should be allowed to drink 1.25 ounces a day.