Answer:
The refrigerator was at around 13 ∘C
Step-by-step explanation:
Newton's Law of Cooling:
The rate of change of a body temperature (amount of heat loss/time of loss) is directly proportional to the difference between its own temperature and the surroundings.
T ⇒ temperature
t ⇒ time
Tenv ⇒refrigerator temperature
⇒ rate of change of he temperature
-h ⇒ constant of proportionality (negative because the temperature is decreasing inside the refrigerator)
We have 3 points:
time (minutes) - Temperature (∘ C)
0 (when the pan was put in the refrigerator) - 46
15 (after 15 minutes) - 27
30 (15 minutes after the first 15 minutes) - 19
= -h (27 - Tenv)
= -h (19 - Tenv)
Now we have a system of two equations and two variables
The refrigerator was at around 13 ∘C
Answer:
Is there an image?
Step-by-step explanation:
Answer:
- multiplying a multi-digit number by itself several times (finding the power of a number)
- finding a square root
- statistical calculations
Step-by-step explanation:
We don't know what your introduction tells you, but the above-listed operations are ones I choose to use a calculator for. I also use a calculator for ordinary arithmetic, such as division by numbers with 2 digits or more. (It is simply faster and requires no scratch paper.)
If statistical calculations are not done with a calculator, they at least require the availability of suitable tables.
___
All of these operations can be done by hand without a calculator, and were in times passed. Lifetimes of effort were involved in generating some of the original math tables for statistics, trig, logarithms, and other functions readily evaluated using a modern calculator.
Answer:
The original number was 54.5.
Step-by-step explanation:
If a number is increased by 2.8%, then it is 102.8% of it's original number.
In mathematics, "of" in virtually all cases means "multiplied by".
Therefore, we do the opposite:
1. Convert to a decimal.
102.8% = 1.028
2. Divide by the decimal.
3. Round it to the nearest tenth.
54.47 rounds to 54.5.
Answer:
Step-by-step explanation:
<u>Simplify the numerator:</u>
- 1/x² + 2/y =
- y/(x²y) + 2x²/(x²y) =
- (2x² + y)/(x²y)
<u>Simplify the denominator:</u>
- 5/x - 6/y² =
- 5y²/(xy²) - 6x/(xy²) =
- (5y² - 6x) / (xy²)
<u>Simplify the fraction:</u>
- (2x² + y)/(x²y) ÷ (5y² - 6x) / (xy²) =
- (2x² + y)/(x²y) × xy² / (5y² - 6x) =
- y(2x² + y) / x(5y² - 6x)
