Answer:
<h2>See the explanation.</h2>
Step-by-step explanation:
a.
The initial length of the candle is 16 inch. It also given that, it burns with a constant rate of 0.8 inch per hour.
After one hour since the candle was lit, the length of the candle will be (16 - 0.8) = 15.2 inch.
After two hour since the candle was lit, the length of the candle will be (15.2 - 0.8) = 14.4 inch. The length of the candle after two hours can also be represented by {16 - 2(0.8)}.
Hence, the length of the candle after t hours when it was lit can be represented by the function,
.
at t = 20.
b.
The domain of the function is 0 to 20.
c.
The range is 0 to 16.
Answer:
400 m^2.
Step-by-step explanation:
The largest area is obtained where the enclosure is a square.
I think that's the right answer because a square is a special form of a rectangle.
So the square would be 20 * 20 = 400 m^2.
Proof:
Let the sides of the rectangle be x and y m long
The area A = xy.
Also the perimeter 2x + 2y = 80
x + y = 40
y = 40 - x.
So substituting for y in A = xy:-
A = x(40 - x)
A = 40x - x^2
For maximum value of A we find the derivative and equate it to 0:
derivative A' = 40 - 2x = 0
2x = 40
x = 20.
So y = 40 - x
= 40 - 20
=20
x and y are the same value so x = y.
Therefore for maximum area the rectangle is a square.
To find the y intercept using the equation of the line, plug in 0 for the x variable and solve for y. If the equation is written in the slope-intercept form, plug in the slope and the x and y coordinates for a point on the line to solve y. Hope this helped! :)