Answer:
a) shown
b) h = [sqrt(17) - (5/2)t]²
c) t = 2sqrt(17)/5 seconds
Step-by-step explanation:
V = pi × r² × h
V = pi × 5² × h
V = 25pi × h
a) dV/dt = dV/dh × dh/dt
-5pi × sqrt(h) = 25pi × dh/dt
dh/dt = -sqrt(h)/5
b) 1/sqrt(h) .dh = -5. dt
2sqrt(h) = -5t + c
t = 0, h = 17
2sqrt(17) = 0 + c
c = 2sqrt(17)
2sqrt(h) = -5t + 2sqrt(17)
sqrt(h) = [2sqrt(17) - 5t] ÷ 2
sqrt(h) = sqrt(17) - (5/2)t
Square both sides
h = [sqrt(17) - (5/2)t]²
c) empty: h = 0
0 = [sqrt(17) - (5/2)t]²
sqrt(17) - (5/2)t = 0
(5/2)t = sqrt(17)
t = 2sqrt(17)/5
t = 1.64924225 seconds
sqrt: square root
Answer:
13
Step-by-step explanation:
Hope this helps.
Let ‘s’ be the son’s age 12 years ago.
Let ‘f’ be the father’s current age.
4 years ago, the son was:
s-4
So, his father is currently:
3(s-4)
=
3s-12
Therefore:
f = 3s-12
In twelve years, the son will be:
s+12
And the father will be:
f+12
This can also be written as:
3s-12+12 as the fathers younger age would be f = 3s+12
=
3s
So, we know that s+12 is half the fathers current age, meaning the father is currently 2(s+12) which is equivalent to 2s+24. Also, we know that the father is currently 3 times the sons age 12 years ago, so 3s (proven by the calculations we made above). Therefore, 2s+24=3s which means 24=s. We can then substitute this, and we will receive 24+12 = 36
Son’s current age: 36
We then substitute the son’s age 12 years ago into 2s+24 to give us the father’s age.
2(24)+24 = 72
Father’s current age: 72
Answer: 4 1/3 or 13/3
Step-by-step explanation:
