Friday

April 18, 2014

April 18, 2014

Total # Posts: 572

**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?

**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!

**Journalism**

Heh...I'm a fiction writer, not a journalist, so it's really hard for me ... The article isn't finished yet - it's barely even started. And it's still kind of choppy because I haven't really done much editing and reordering and stuff just yet. [There ar...

**Journalism**

Maybe I could just start with a question?

**Journalism**

I tried writing the opening to my article on vegetarianism and this is what I got so far. [A lot of people like to sit down at night and eat a big, juicy steak – and then there are those who prefer an organic meal without any meat. Vegetarianism is not uncommon, but it...

**Journalism**

I've started working on an article for my Journalism class about vegetarianism - pros and cons, and why or why not people at my school support it. I've gotten a few paragraphs in, but I'm having trouble on writing the lead. Any suggestions?

**Phyics**

to find the distance multiply radius*2 and then take that answer and multiply it by pi (3.14) to get the total distance around lake then multiply the total by 0.75 to get answer for the distance traveled

**Physics**

A bowling ball traveling with constant speed hits the pins at the end of a bowling lane 16.5 m long. The bowler hears the sound of the ball hitting the pins 2.51s after the ball is released from his hands. What is the speed of the ball? The speed of sound is 340 m/s

**Physics**

A stone is thrown vertically upward with a speed of 19.0m/s How fast is it moving when it reaches a height of 10.0m

**Math**

Describe the intervals on which the following function is continuous. If not continuous, state "where" the discontinuity occurs and state the TYPE of discontinuity. f(x)= (x^2-x-12)/(x^2-6x+8) I just don't understand how to find the intervals. Thanks~

**math**

Find the exact value of 1. tan 75 degrees 2. Cos 15 degrees 3. Sin 105 degrees

**math**

Two pieces of wire are stretched from the top M, of a vertical pole to the points L and N on the horizontal ground, The angle of depression of L from M is 65 degrees. N is on the opposite side of the pole (from L) at an angle of depression of 72 degrees from M. N is 4m from th...

**math**

Dave walked from point A to point B due North East for a distance of 20m. He immediately changed direction and walked 50m from B to C on a bearing of 110 degrees. i. Calculate the distance AC ii. Find the bearing of C from A

**math**

Dave walked from point A to point B due North East for a distance of 20m. He immediately changed direction and walked 50m from B to C on a bearing of 110 degrees. i. Calculate the distance AC ii. Find the bearing of C from A

**math**

Prove that Sin x + tan x / 1+cosx =tan x

**math**

If the bearing fron H to G is 098 degrees, what is the bearing of G from H

**math**

Solve the equation 8 cos^2 X -2 =0 given that 180< or equal to X <or equal to 360 degrees.

**math**

Triangle DEF is such that DF=8cm,EF=5.5cm and its area is 11 root2 cm^2. Find angle EFD.

**math**

Given the function y= 4cos(2x+90degrees)-3, Find the value of y when x =30 degrees.

**math**

Simplify cos Theta/4 cos theta/4 - sin theta/4 sin theta/4.

**math**

Triangle XYZ with vertices X(3,-1) Y(7,-3)Z(3,-5) undergoes an enlargement represented by the mapping: (x)--(-0.5 0)(x) +(-3) (y)--( 0 -0.5)(y) +(4) Evaluate: 1. The vertices of the image of triangle XYZ. 2. The centre of enlargement PS. The small brackets should be one big br...

**math**

Triangle XYZ with vertices X(3,-1) Y(7,-3)Z(3,-5) undergoes an enlargement represented by the mapping: x

**math**

Three students, Chris, Vlad, and Steve, are registered for the same class and attend independently of each other. If Chris is in class 80% of the time, Vlad is in class 85% of the time, and Steve is in class 90% of the time, what is the probability that at least two of them ar...

**math**

The 9th term of an AP is 8 and the 4th term is 20. Find the first term and the common difference.

**math**

find the exact value of [sec(-30 degrees)- cot 120 degrees]/1-cosec^2(45 degrees) Find the exact value of [sin^2(355 degrees) + cos^2 (355 degrees)]/ tan^2 (30 degrees)

**math**

This is a matrix question. R is the matrix (3r 1) (s 2s) 1. State, in terms of s and r the determinant of R 2. If r=1/3 and s=4 determine the inverse of R 3.State the pair of r and s not including 0, which would make the matrix R a singular matrix

**math**

This is a matrix question. R is the matrix (3r 1) (s 2s) 1. State, in terms of s and r the determinant of R 2. If r=1/3 and s=4 determine the inverse of R 3.State the pair of r and s not including 0, which would make the matrix R a singular matrix

**math**

This is a matrix question but I can't get a single bracket so I will use two. (a b)(5 1) =(12 -2) (3 0)(-2 4) (15 3) Find the values of a and b.

**math**

A sequence is generated by the recurrence relation Ur+1 = 1/Ur -3. Given that U2 = U1 find the possible of U1

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