Wednesday
July 30, 2014

Posts by Lindsay


Total # Posts: 600

math
Show that 4/2^x = 2^2-x and hence or otherwise solve for x in the equation 2^x +2^x-2 =5

math
27 root 3 =3^b. Find the value of b.

physics
The electron in a certain hydrogen atom has an angular momentum of 6.834 × 10-34 J·s. What is the largest possible magnitude for the z component of the angular momentum of this electron? For accuracy, use h = 6.626 × 10-34 J·s. I know you need to use ...

math
An A.P. is given by k,2k/3,k/3, 0,... Find the 6th term.

algebra
Find 1. the binomial expansion of (3+2x)^5 simplifying terms. Hence find the binomial expansion of (3+2x)^5 +(3-2x)^5.

algebra
Find 1.The first 4 terms of the binomial expansion in ascending powers of x of (1+x/4)^8. 2.Use your expansion to estimate (1.025)^8

math
Find the first three terms in ascending power of 'x' of the binomial expression of (3+bx)^5 where b is a non zero constant.

math
A series is defined by 8+4+2+1+1/2+1/4+...+1/32 Write the series in sigma notation

math
find the sum of an A.P.of eleven terms whose first term is 1 and whose last term is 6.

math
The sum of the first 20 terms of an arithmetic series is identical to the sum of the first 22 terms. If the common difference is -2, find the first term.

math
a 40 year building programme for new houses began in 1951(year 1) and finished in 1990 year (40). The number of houses built each year form an A.P. With the first term 'a' and the common difference 'd'. Given that 2400 new houses were built in 1960 and 600 new ...

math
Given that 2 log base2 (x+15) - log base2 x = 6 1.Show that x^2 -34x +225 = 0 2. Hence or otherwise solve the equation 2 log base 2 (x+15) - log base 2 x =6

math
Solve 4^y -7(2^y) = 8

math
Solve 3 log x = 1 + log (4x+5)/ log 2

math
Given that x = 2log t is a solution of the equation10^(2x+1) -7(10^x) -26 =0. Find t

physics
The drawing shows an equilateral triangle, each side of which has a length of 4.53 cm. Point charges are fixed to each corner, as shown. The 4.00 C charge experiences a net force due to the charges qA and qB. This net force points vertically downward and has a magnitude of 779...

maths
How did you arrive at 10^2?

maths
Solve log(5x-1) = 2 + log(x-2)

maths
Given that x=lg a is a solution of the equation 10^(2x+1)-7(10^x) =26. Find the value of a.

math
solve the equation for x. 3^2x - 3^x+2 +8 =0 Ps. The topic is logarithmic and exponential functions

geometry
A floor measures 10m by 5m is to be covered with flooring boards measuring 1m 20cm. How many flooring boards would be needed to cover this section.

Stats.
Okay, never mind I think I got this one....

Stats.
Another one that I need help.... At Ajax Spring Water, a half-liter bottle of soft drink is supposed to contain a mean of 520 ml. The filling process follows a normal distribution with a known process standard deviation of 4 ml. (a) Which sampling distribution would you use if...

Stats.
I don't know where to begin with this one.... When told that over a 10-year period a mammogram test has a false positive rate of 50 percent, Bob said "That means that about half the women tested actually have no cancer". Correct Bob's mistaken interpretation.

Physics/ Chem
Find the entropy change when 51g of steam condenses to water at 100 ∘C.

Physics
A cylinder with a movable piston encloses 0.39 mole of ideal gas at 308K . How much heat is required to increase its volume isothermally by a factor of 3? 1100J 1400J 1600J 550J

Statistics
Daily output of Marathon's Grayville, LA, Refinery is normally Distributed with a mean of 232,000 barrels of crude oil per day with a standard deviation of 7,000 barrels. a. what is the probability of producing at least 232,000 barrels? b. between 232,000 and 239,000 barre...

Stats.
how do I use it?

Science
Natural selection.

math
Solve this equation for x Log3^2x+5 =1

Science
1. ? 2. c 3. c 4. ? 5. b 6. d 7. c 8. a 9. ? 10. b

Science
I don't even understand it, it's not a test.

Science
1. Compare the two light waves above. Which wave would produce the brightest light and which wave would have the least energy? a. wave A; wave A b. wave A; wave B c. wave B; wave A d. wave B; wave B 2. Which waves have the longest wavelength and lowest energy on the electromag...

Science
CAN SOMEONE HELP WITH MY HOMEWORK?

math
0.06 2/3 into a fraction

Calculus
The total stopping distance T of a vehicle is T=2.5x+0.5x^2 where T is in feet and x is the speed in miles per hour. Approximate the change and percent change in total stopping distance as sped changes from x=25 to x=26 miles per hour. I started taking the derivative, but that...

Calculus (check my work)
You realize I'm a terrible Calculus student? I don't understand the concepts that the other students can pick up on right away. I don't really get why you did any of what you did, and there aren't any examples like this one in our book for me to look back on.

Calculus (check my work)
Okay, I really don't understand how you did any of that. What's the point of half of it? I tried to do some of what you did, but I got different numbers for my answers.

Calculus (check my work)
Also, it says to estimate the maximum allowable percent error in measuring the circumference if the error in computing the area cannot exceed 3%. How do I do this?

Calculus (check my work)
The measurement of the circumference of a circle is found to be 64 centimeters, with a possible error of 0.9 centimeter. Approximate the percent error in computing the area of the circle. MY ANSWER 8.83%

Calculus (check my answer)
No, this is a different part of that same problem. It asks for the surface area this time, not volume.

Calculus (check my answer)
The measurement of the edge of a cube is found to be 15 inches, with a possible error of 0.03 inch. Use differentials to approximate the maximum possible propagated error in computing the surface area of the cube. I got 5.4 inches squared. Is this right?

Calculus (check my answers)
Thank you soooo much!

Calculus (check my answers)
Never mind number 20! Someone already helped me with it!

Calculus (check my answers)
10) Use the information to evaluate and compare delta y and dy. y=2-x^4, x=2 and delta x=dx=0.01 MY ANSWER: dy=-.32 and delta y=-.3224. Are they supposed to be negative, and how do I compare those in words? I don't even understand what I was supposed to do... 12) Find the ...

Calculus
Hold on...I think I just managed to kind of figure it out!

Calculus
Wait, I'm not understanding how you get the tanx -x part...

Calculus
Find the differential dy of the given function. y=sec^2x/(x^2+1) My answer was [tanx(x^2+1)-2sec^2x]dx/(x^2+1)^2 My friend (who's a lot smarter than me) got something wayyy different, so I'm not sure if I'm doing this wrong...?

Calculus
Consider the function x^2+x-4 Estimate the area between the graph and the x-axis between x=2 and x=4 using four rectangles and right end points.

Calculus
The measurements of the base and altitude of a triangle are found to be 36 and 50 centimeters, respectively. The possible error in each measurement is 0.25 centimeter. Use differentials to approximate the possible propagated error in computing the area of the triangle.

Calculus
Please, don't assume that we've been taught this stuff because we were literally just handed a packet and told to learn it ourselves. I don't understand this in the slightest. The question is: Use the information to evaluate and compare delta y and dy. y=2-x^4, x=2...

Calculus
Wait, never mind. I'm overthinking it and I made a dumb mistake. Disregard these two answers.

Calculus
Hold on; I think I did delta y wrong. If you set it up like that, then you would get 2-(4.01)^4 -2+2^4. And you get a ridiculous number...?

Calculus
Please, don't assume that we've been taught this stuff because we were literally just handed a packet and told to learn it ourselves. I don't understand this in the slightest. The question is: Use the information to evaluate and compare delta y and dy. y=2-x^4, x=2...

math
Solve /3x + 12/ >= 21 PS>= means is greater than or equal to.

Calculus
I know that; don't know why I didn't use it. Oops. How do you get 0 from f(x)?

Calculus
Use the information to evaluate and compare (triangle)x and dy. y=2-x^4, x=2, and (triangle)x=dx=0.01

math
Factorize b^4-16 PS. "b" is really the letter b

math
Solve 16(4^2x-1)= 8^x+3

math
Change 1010101011 base 2 to base 4

math
If 203n + 2m4n = 501n. a. Find the value of base n. b. Find the value of m PS the 'n' is really base n.

math
f(x) =x-2/x-3. I calculated f^-1 (x)to be 3x-2/y-1. How do I use f^-1 (x) to evaluate (x-2/x-3)=4. P.S/ f^-1 means 'f' inverse.

Calculus (Please check my work.)
Also, for 5, is the marginal cost at 31 $186?

Calculus (Please check my work.)
Thanks so much for pointing those things out! But I do have a question on #2? How'd you get the 6 for the maximum profit? I got the equation -4x^2+48x-18, but I couldn't get the 6. (It's probably some really stupid mistake. I make a lot of those. hahaha)

Calculus (Please check my work.)
This is my last chance to make at least a C in my AP Calculus course, so please tell me if I got these right or wrong so that I can fix them before it's due. Also, there was one I wasn't sure how to do, so if you can help me with that, it would be much appreciated! 1)F...

Calculus
How do you show that the minimum average cost occurs when the average cost equals the marginal cost?

math
Solve (x^3 y)^2/8x^1/3

math
solve the following inequality /3x + 12/ >/ 21 PS >/ means greater than or equal to.

Calculus PLEASE HELP
Show that the maximum profit occurs when the marginal revenue equals the marginal cost. I'm pretty sure this is supposed to be some sort of proof, but I have no idea how to even start it...

Calculus
Show that the maximum profit occurs when the marginal revenue equals the marginal cost. I'm pretty sure this is supposed to be some sort of proof, but I have no idea how to even start it...

math
What is the negation of p and q?

math
solve the following absolute value question /4x + 5/ =25

math
The equation kx^2 -2x-7=0 has two real and identical roots, find the value of k.

maths
The following statement defines a relation R in the natural numbers N. state whether or not each relation is symmetric 1. x is less than or equal to y 2. x+y =10

Calculus
Never mind, I got it!

Calculus
Y=5x^4 -24x^3+24x^2+17 is concave down for which interval? A) x<0 B) x>0 C) x<-2 or x>-2/5 D) x<2/5 or x>2 E) 2/5 < x < 2 I know you take the second derivative...but I keep getting stuck with something that won't factor right?

Calculus
If x^2=25-y^2, what is the value of [(d^2)(y)]/(dx^2) at the point (3,4)?

Math
Okay, well, I don't know how the tracher's getting her answers then.,.

Math
Factor 5x^2 -6x-4 I must be having an off day or something; this can factor, right!?

Calculus PLEASE HELP
Given that C(x)=2x^3-21x^2+36x+1000 is a cost function, determine the intervals for which the cost is increasing. Determine any intervals for which the marginal cost is increasing. Marginal cost is when you derive the cost function, correct? So do you do the second derivative ...

Calculus
Given that C(x)=2x^3-21x^2+36x+1000 is a cost function, determine the intervals for which the cost is increasing. Determine any intervals for which the marginal cost is increasing. Marginal cost is when you derive the cost function, correct? So do you do the second derivative ...

Calculus
Using the equations R(x)=-x^2+400x and C(x)=x^2+40x+100, find the Maximum Revenue

Calculus (check my work)
Yes! Thank you! I do have another question, though. The second part of the problem says to "compare R(11) -R(10) with that result." Does that mean that I derive it before plugging in 11 and 10 or...?

Calculus (check my work)
Find the marginal revenue at x=10 using the equation R(x)=-x^2+80x Is the answer 60?

Calculus
Find the maximum revenue using the following equations: R(x)=-x^2 +400x and C(x)=x^2+40x+100. What I've done so far is use R(x) and solve for x, which got me 0 and 400. Is that how you're supposed to start it? What happens next? (I apologize; I'm really bad at teac...

Calculus
Ohhhh. I see what I did wrong in that second one! Thanks for all your help!(:

Calculus
Check my work? The equations given were R(x)=-x^2+400x and C(x)=x^2+40x+100. We were asked to find the maximum profit and minimum average cost. (I'm having trouble remembering how to find a minimum and maximum, so please help with that, if you can!) For Max Profit, I got $...

Calculus
I don't remember how to did min/max. I can get as far as the critical numbers...

Calculus
How do you find maximum revenue, maximum profit, and minimum average cost? Our teacher gave us a project to teach ourselves the section, but I can't learn very well even with her teaching, so I don't know how I'm supposed to do this...

Calculus
That helped a whole lot! Thank you so much!

Calculus
Find limit as x->-3 of (sin(4x+12))/(5x+15)

Math
Let f(x)= lim as h->0 of ((x+h)^2-x^2)/ h. For what value of x does f(x)= 4?

Calculus Please Help!!
Thanks! When it asks to find the rate the area is changing at that point in time, did you get the answer -357/5? Because I did, but it doesn't seem right...

Calculus Please Help!!
"A 13-foot ladder is leaning against a building when its base begins to slide away from the base of the building. By the time the base is 12 feet from the building, the base is moving at the rate of 6 ft/sec. How fast is the top of the ladder sliding down the wall at that...

CALCULUS HELP!!
I haven't done this type of problem in a while, so if someone can just show me how to set it up, I can figure out the rest. (: "A 13-foot ladder is leaning against a building when its base begins to slide away from the base of the building. By the time the base is 12 ...

Chemistry
How much energy would be needed to turn 183.7 g of Ice at -27 degrees celcius to steam at 135 degrees celcius?

BIO
Explain why routine blood measurement of glycated hemoglobin is used to determine whether a diabetic has good glucose control.

Calculus
Determine if Rolle's Theorem can be applied. If it can, find all values of c such that f'(c)=0. f(x)=x^3-9x, [-3,3]

Creative Writing
Need help describing something. I'm not good at writing horror or graphic death and such. In my story, a tree's branches basically 'come to life,' but I'm not sure what kind of details to use for the branches if they're like elastic and bend and twist l...

Journalism
Hmmm....That one would be okay, I suppose. Might attract more people. Thanks!

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