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Tutors Answer Your Questions about Linear Algebra (FREE)
Question 109443: Help, I am trying to help my daughter with her homework, don't know what I'm doing. Hope you can help.
Calorie consumption problem: Lansburg's Weather and Health reports data gathered during World War II which shows that people use about 35 more calories per day for each 1 degree drop in the Celsius temp. At 20 degrees C, a working person uses about 2900 calories per day.
a) Explain how you know that the calorie consumption varies linerarly with the temp. What is the slope? write the equation.
b) How many calories per day would a working person use:
in the Sahara Desert wht eht temp is 50 C.
in Antarctica in August when the temp is -50 C.
c) At what temp does your model predict that a working person would use no calories at all.
d) Do you think the linear function gives meaningful answers for temp this hot?
e) Sketch a graph of the function using a reasonable domain.
Click here to see answer by stanbon(26259)   |
Question 109725: My daughters math problems are making me crazy, hope you can help me so I can help her.
Speed on a hill problem: The maximum speed your car will go is a linear function of the steepness of the hill it is going up or down. Suppose that the car can go a maximum of 63 mph up a 2 degree hill, and a max of 105 mph down a 5 degree hill. (going downhill can be thought of as going up a hill at -5 degrees).
a) Write a particular equation expressing max speed in terms of steepness.
b) How fast could you go down a 7 degree hill?
c) If your top speed is 83 mph, how steep is the hill? Is it up or down?
d) What does the speed-intercept equal, and what does it represent?
e) What does the steepness-intercept equal and what does it reprsent?
f) Sketch and label the graph using a reasonable domain.
Click here to see answer by stanbon(26259) |
Question 109727: I need some help with my daughters homework as I don't know what I'm doing, hope you can help.
Thermal expansion problem: Bridges on expressways often have expansion joints which are small gaps in the roadway between one bridge section and the next. The gaps are put there so that the bridge will have room to expand when the weather gets hot. Suppose that a bridge has a gap of 1.3 cm when the temp is 15 degrees C, and the gap narrows to 0.7 cm when the temp warms to 25 degrees C. Assume that the gap width varies linearly with the temp.
a) Write the particular equation for gap width as a function of temp.
b) How wide would the gap be at 35 degrees C? At -10 C
c) At what temp would the gap close completely? What mathematical name is given to this temp?
d) Would the temp ever be likely to get hot enough to close the gap?
e) Sketch the graph using an appropriate domain.
Thank you for any help you can give me
Brian
Click here to see answer by ankor@dixie-net.com(6691)  |
Question 110813: I have to answer the following question and I am having a hard time. Can you please help?
Find a real-life application of a linear function. State the application, give the equation of the linear function, and state what the x and y in the application represent. Choose at least two values of x to input into your function and find the corresponding y for each. State, in words, what each x and y means in terms of your real-life application.
Click here to see answer by josmiceli(3003) |
Question 111072: This is not from a book, but I desperately need it answered in the next couple hours. I've tried all evening and cannot get the correct answer! Help!
A radioactive element sodium-24 has a half-life of 14 hrs. and is used to help locate obstructions of blood flow. A procedure requires 0.9 grams and is scheduled to take place in 43 hours. The rate of decay of sodium-24 is 5%.
What is the minimum amount of sodium-24 that must be on hand now?
At least ____ years. (Answer should be accurate to two decimal places.)
Thanks!
Click here to see answer by stanbon(26259) |
Question 111072: This is not from a book, but I desperately need it answered in the next couple hours. I've tried all evening and cannot get the correct answer! Help!
A radioactive element sodium-24 has a half-life of 14 hrs. and is used to help locate obstructions of blood flow. A procedure requires 0.9 grams and is scheduled to take place in 43 hours. The rate of decay of sodium-24 is 5%.
What is the minimum amount of sodium-24 that must be on hand now?
At least ____ years. (Answer should be accurate to two decimal places.)
Thanks!
Click here to see answer by scott8148(3382)  |
Question 113489: Solve the system of equation using the addition elimination method if the answer is a unique solution, present it as an ordered pair (x,y). if not specify whethere the answer is no solution or infinitely many solutions.
9x+2y =2
3x+5y =5
Click here to see answer by MathLover1(1183)  |
Question 113523: Solve the system of equations using the addition elimination method. If the answer is a unique solution present it as an ordered pair (x,y) if not specify whether the answer is no solution or infinitely many solutions
3x - 11y =9
-9x + 33y = 18
Click here to see answer by stanbon(26259) |
Question 113541: Please help. Please understand that I am not sure what topic to pick for this
question but i really need help, please.
Solve the following system of linear inequality by graphing
3x - y ≤ 6
x ≥ 1
y ≤ 3
Thanks
JMS
Click here to see answer by elima(1433) |
Question 115823: Text Book - Beginning and Intermediate Algebra with Applications and visualization. Page 236-288.
Question- The graph of the system 2x+y=5
4x-3y=-5 shows an intersection at the point
(1,3). What does the
intersection mean algebraically?
Click here to see answer by josmiceli(3003) |
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