Tutors Answer Your Questions about Exponential-and-logarithmic-functions (FREE)
Question 269857: This is more of a theoretical question:
When the logarithm is written as log(a)y = x. The "a" is called the base, but what is the x and y called? (Similarly, in y=a + bsin (x-c) + d, the "a" would be the amplitude, the "b" would be the period, ect).
Thank you very much!!
Click here to see answer by jim_thompson5910(35256) |
Question 270301: Solve for X, Y, and Z in the following systems of three equations using either substition or elimination methods:
a. X 2Y Z = 22
X Y = 15
3X Y Z = 37
b. 10X Y Z = 603
8X 2Y Z = 603
20X - 10Y - 2Z = -6
c. 22X 5Y 7Z = 12
10X 3Y 2Z = 5
9X 2Y 12Z = 14
Click here to see answer by jim_thompson5910(35256) |
Question 270731: This life expectancy problem is really messing up when I try to solve it....
L(x)=79.25/(1+9.7135 * 10^24 * e^-.0304t)
* = multiply
^ = to the power of (ex: 5^7 Five to the seventh power)
Solve this equation when t=1970, and when t=1992.
I keep getting a weird decimal for t=1970, and somewhere around four thousand for t=1992. Can I have some help? Thanks!
Click here to see answer by Alan3354(69443)  |
Question 270977: Please help; I have tried for 2 pages of work--
What is the approximate solution of 3 to the x+1 power = 5 to the x power?
Answer choices: a. 2.1507 b. 14l.4686 c. 0.4651 d. -0.4651
Thank you very much-Elizabeth
Click here to see answer by vleith(2983) |
Question 272255: I am trying to solve this problem, and the answer is in the back of the book, but I keep getting the wrong answer. First for the problem: Tree Density:Ecologists studies the spacing between individual trees in a forest in Britsh Columbia. This lodgepole pine forest was 40 to 50 years old and had approximiately 1600 trees per acre that are randomly spaced. The probablity or liklihood that there is at least one tree located with a radius of x feet is estimated by P(x) =1-e^-0.1144x. For example, P(7)≈0.55 means that if a person picks a point at random in the forest, there is a 55% chance that at least one tree will be located within 7 feet.
a) Evaluate P(2) and P(20), and interpret the results.
b) Graph P. Explain verbally why it is logical for P to be an increasing function. Does the graph have a horizontal asymptote?
c) Solve P(x)=0.5 and interpret the results.
I keep getting the wrong answer. Here is what I came up with. I cannot figure out how to do the graphing part. I have the TI-Nspire, but outside of logs, I mostly use the TI-84 keypad. Here is my workup. 1 – e-0.1144x = 0.5
e-0.1144x = 0.5
ln(e-0.1144x) = ln(0.5)
-0.1144x = ln(0.5)
ln(0.5)
x = ---------- = 6.1
0.1144
I got that there is 0.5, or 50%, probability to find another tree in the circle with the radius 6.1 ft around. The actual answer in the back of the book . Here it is word for word.
a) P(2)≈0.20 and P(20) ≈ 0.90. There is a 20% chance that at least one tree is located within a circle having radius 2ft and a 90% chance for a circle having a radius 20 ft.
b) The larger the circle, the more likely it is to contain a tree. Y=1; probability cannot be greater than 1. They then show a graph with a window of [0, 25, 5] by [0, 1, 0]. But, I don’t know what to put in for Y1 or any others if needed.
c) x≈6.1. A circle of radius 6.1 ft has a 50-50 chance of containing at least one tree.
Thanks so much.
Click here to see answer by stanbon(75887) |
Question 273686: We are stumped on this problem:
Simplify. Leave in radical form: (cube root 5^2.7)/(cube root 5^4.5)
The answer is 1/(fifth root 5^3)
Any help showing the process would be much appreciated. Thank you!
Michelle and Cecil Jones
Click here to see answer by richwmiller(17219)  |
Question 273741: I am trying to solve this problem. I get how to do part A. I don’t know how to graph this. What do I put for Y1 and Y2 (if anything)? And on part C. How did it come to about 7 miles? I don’t understand where that comes from. The answer is in the back of the book. I have the TI-Nspire, but mostly use the TI-84 Silver Edition keypad.
The question is: Hurricanes are some of the largest storms on earth. They are very low pressure areas with diameters over 500 miles. The barometric air pressure in inches of mercury at a distance of x miles from the eye of a severe hurricane is modeled by the formula f(x) =0.48 ln (x+1) +27. It states
a) Evaluate f(0) and f(100).
b) Graph f in [0, 250, 1] by [25, 30, 1]
c) At what distance from the eye of the hurricane is the air pressure 28 Inches of mercury?
Thank you....
Click here to see answer by solver91311(24713)  |
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