# Posts by leanna

Total # Posts: 118

**math**

You find a sales receipt from a store that shows the total price as $40, and the total amount paid including sales tax as $42. a. Write an equation you can use to find the sales tax rate which is r. what is the equation so I tried all things I could think of but it doesn't...

*February 6, 2017*

**Calculus**

A smokestack deposits soot on the ground with a concentration inversely proportional to the square of the distance from the stack. With two smokestacks d miles apart, the concentration of the combined deposits on the line joining them, at a distance x from one stack, is given ...

*March 26, 2016*

**Calculus**

The table below shows some values of a linear function f and an exponential function g. Fill in exact values for each of the missing entries. X 0 1 2 3 4 f(x) 25 375 g(x) 25 375

*January 19, 2016*

**Calculus**

Suppose that f(t)=Qoa^1=Qo(1+r)^t with f(4)=72.2 and f(10)=176.7. Find what a is and what r is.

*January 19, 2016*

**Chemistry**

A sample of nitrogen gas was collected via water displacement. Since the nitrogen was collected via water displacement, the sample is saturated with water vapor. If the total pressure of the mixture at 21 °C is 1.16 atm, what is the partial pressure of nitrogen? The vapor ...

*December 9, 2015*

**Chemistry**

A sample of nitrogen gas was collected via water displacement. Since the nitrogen was collected via water displacement, the sample is saturated with water vapor. If the total pressure of the mixture at 21 °C is 1.16 atm, what is the partial pressure of nitrogen? The vapor ...

*December 9, 2015*

**math**

Lee wants to cut this piece of canvas into two rectangles that are 3×2 and 3×5. He wants the sum of the two small recyangles to be the same as the area of the large rectangle. Can he do this? Explain the rectangle is 6feet across and 3feet tall

*April 29, 2015*

**Chemistry :/**

Formulas for experiment 1: CuSO4*5H2O CuSO4.XH2O --------> CuSO4 + XH2O Formulas for experiment 2: MgCl2·6H2O MgCl2 * X H2O = MgCl2 + X H2O I just need someone to check my answers please :)

*March 7, 2015*

**Chemistry :/**

These are the calculations I can up with for experiment 1: a:mass of water in the hydrate sample (g) 1.804g b:number of moles of water in the sample 0.100g c:mass of pure salt in the sample (g) 3.196g d:number of moles of salt in the sample .0214g e:molar ratio of water to ...

*March 7, 2015*

**Chemistry :/**

Experiment 1 results: mass of crucible 88g mass of hydrate 93g mass of salt 91.196g 1. Calculate the following: a:mass of water in the hydrate sample (g) b:number of moles of water in the sample c:mass of pure salt in the sample (g) d:number of moles of salt in the sample e:...

*March 7, 2015*

**Chemistry**

Experiment 1 results: mass of crucible 88g mass of hydrate 93g mass of salt 91.196g 1. Calculate the following: a:mass of water in the hydrate sample (g) b:number of moles of water in the sample c:mass of pure salt in the sample (g) d:number of moles of salt in the sample e:...

*March 7, 2015*

**Physics**

Two 2.9-cm-diameter electrodes with a 0.15-mm-thick sheet of Teflon between them are attached to a 9.0 V battery. Without disconnecting the battery, the Teflon is removed. a) What are the electric field after the Teflon is removed?

*October 6, 2013*

**Art**

I'm in art and i cant draw a bear do you have any tips?

*September 24, 2013*

**math**

I im learningabout fractions is there an faster or easier way i can do them?

*September 24, 2013*

**math**

OH THATS EASY XD well how much is in a millimeter? you need to find that out then..............yea that's all i got i think you x the number of what you got of the milliter and x it by 30

*September 24, 2013*

**Physics**

Suppose you wish to make a vertical leap with the goal of getting your head as high as possible above the ground. At the top of your leap, your arms should be... a. held at your sides. b. raised above your head. c. outstretched, away from your body.

*April 1, 2013*

**Physics**

A combination lock has a 1.2 cm -diameter knob that is part of the dial you turn to unlock the lock. To turn that knob, you grip it between your thumb and forefinger with a force of 0.62 N as you twist your wrist. Suppose the coefficient of static friction between the knob and...

*April 1, 2013*

**Physics**

A combination lock has a 1.2 cm -diameter knob that is part of the dial you turn to unlock the lock. To turn that knob, you grip it between your thumb and forefinger with a force of 0.62 N as you twist your wrist. Suppose the coefficient of static friction between the knob and...

*March 31, 2013*

**Physics**

1. At what height above the earth is the free-fall acceleration 30% of its value at the surface? 2. What is the speed of a satellite orbiting at that height?

*March 24, 2013*

**Physics**

The ultracentrifuge is an important tool for separating and analyzing proteins in biological research. Because of the enormous centripetal accelerations that can be achieved, the apparatus must be carefully balanced so that each sample is matched by another on the opposite ...

*March 24, 2013*

**Physics**

A conical pendulum is formed by attaching a 0.60kg ball to a 1.0m -long string, then allowing the mass to move in a horizontal circle of radius 30cm. 1. What is the tension in the string 2. What is the ball's angular velocity in rpm?

*March 21, 2013*

**Physics**

A fast-moving superhero in a comic book runs around a circular, 70-m-diameter track five and a half times (ending up directly opposite her starting point) in 3.0s. What is her angular speed, in rad/s?

*March 8, 2013*

**Physics**

A 20 kg crate is placed on a horizontal conveyor belt. The materials are such that us = 0.47 and uk = 0.21. What is the maximum acceleration the belt can have without the crate slipping? If acceleration of the belt exceeds the value determined in part A, what is the ...

*March 3, 2013*

**Physics**

(23kg)(9.8m/s^2)(cos(38)) = 177.6N

*March 3, 2013*

**Physics**

A 23 kg child goes down a straight slide inclined 38 degrees above horizontal. The child is acted on by his weight, the normal force from the slide, and kinetic friction.

*March 3, 2013*

**math**

when a ball is dropped, it bounces back up 4/5 of the height from the height it was dropped.If the ball dropped from a height of 200cm, how high does it go after bouncing twice.

*February 9, 2013*

**math**

a woman had 400 oranges in a basket. after selling 1/5 of them, she found that 1/8 of the remainder were bad. how many of the remainder were good?

*February 9, 2013*

**math**

how do you write 4/5, 5/12, 3/10 in its simpliest form?

*January 18, 2013*

**algebra**

The cost in dollars, C, of renting a carpet cleaner is given by the linear equation C = 20 + 25x, where x is the number of days. Use this model to find the cost of renting the unit for 11 days.

*January 9, 2013*

**Math**

There are 144 perfect pumpkins.

*November 22, 2012*

**Science Help!**

How much heat is needed to cause the following irreversible reaction? 200 g of liquid H2O at 50°C is heated to form 200 g of steam at 120°C

*October 22, 2012*

**Organic Chemistry**

I have the linear formula of CH3CH2OLi and I'm trying to draw the structure with charges. Not really sure how. Please help.

*September 18, 2012*

**Math**

The size of a bacteria population is given by P=C*e^(kt) Where C is the initial size of the population, k is the growth rate constant and t is time in minutes. a) If the bacteria in the population double their number every minute, what is the value of k? I need help please!

*March 6, 2012*

**social studies**

How did minoans and Mycenaeans make a living? Who was Socrates most well known student? What was the name of the book plato wrote?

*January 17, 2012*

**Probability**

With her box of 64 crayons, your little sister decides to draw a picture of the family: herself, you, and your parents. How many different ways could she find to give you all hair colors?

*November 10, 2011*

**Probability**

With her box of 64 crayons, your little sister decides to draw a picture of the family: herself, you, and your parents. How many different ways could she find to give you all hair colors?

*November 10, 2011*

**Biology**

The options are: 3.549 g 35.49 g 35.49 mg 0.1 g 0.1 mg

*October 20, 2011*

**Biology**

You are supposed to add 0.1 mol of a substance with molecular weight = 354.9 to 1 liter of water. How much should you add? Choose one.

*October 20, 2011*

**Biology**

In goats, the allele for black hair is dominant to that for red. Two black haired goats mated, producing twelve offspring. Of the first eleven, 8 had black hair and 3 had red hair. What is the probability of the twelfth offspring having red hair?

*October 16, 2011*

**Grammar MT**

It actually depends on account instructions on dropping the 's. Both are correct.

*August 13, 2011*

**Calc**

When pi/2<theta<3pi/4, which of the following could possibly be tan theta. a. -8 b. -1/8 c. 0 d. 1/8 e. 8

*July 15, 2011*

**Calc**

Thank you so much!

*July 12, 2011*

**Calc**

I need help solving this problem. logbase5(x+2)=2

*July 12, 2011*

**Calculus**

Thanks for help on 1. on 2. if i do u=sqrt(x) my du is 1/2x^(-1/2) and that means my du is in the denominator. So it would read 2integral of sin(u)/du

*April 11, 2011*

**Calculus**

I don't know how to do the integral of e^(lnx^2)dx and the integral of (sin sqrtx)/(sqrtx) dx

*April 11, 2011*

**Calculus**

oh wow thank you so much!! that makes sense!!

*April 11, 2011*

**Calculus**

i know that the derivative of that is 1/2x^(-1/2) i still don't know what to do

*April 11, 2011*

**Calculus**

I need help with integrals and I need help with the problem. Integral of 4/sqrt(x)dx

*April 11, 2011*

**Algebra**

How do you do long division of ((5x^4)-2)/(3x^2) _______ 3x^2|5x^4-2

*April 11, 2011*

**AP Calculus**

I previously posted this but had a mistake in it. Determine dy/dx if xsiny=arctany i did (x)(cosy dy/dx)+(1)(siny)=dy/(1+y^2) so far

*March 23, 2011*

**AP Calculus**

Determine dy/dx if xsiny=artany i did (x)(cosy dy/dx) so far

*March 23, 2011*

**chem**

a 275mL sample of vapor in equilibrium with 1-propylamine at 25C is removed and dissolved in 0.500L of H20. For 1-propalamine, Kb=3.72*10^-4 and the vapor pressure at 25C is 215 torr. (a)What should be the pH of the aqueous solution? (b) How many mg of NaOH dissolved in 0.500L...

*March 22, 2011*

**AP Calculus**

Find the total area enclosed by the graph of y=(e^sinx)*(cosx) and the x-axis from x=0 to x=pi I got .0563331993 but when I checked it graphically I got 3.22765

*March 6, 2011*

**Calculus**

Let f be the function defined for x >or= to 0 with f(0)=5 and f', the first derivative of f, give by f'(x)=e^(-x/4)sin(x^2). A) Use the graph of f' to determine whether the graph of f is concave up, concave down, or neither on the interval 1.7<x<1.9. ...

*February 9, 2011*

**Calculus**

A cubic polynomial function f is defined by f(x) = 4x^3 + ax^2 + bx + k? A cubic polynomial function f is defined by: f(x) = 4x^3 + ax^2 + bx + k where a, b, and k are constants. The function f has a local minimum at x= -1, and the graph of f has a point of inflection at x= -2...

*February 9, 2011*

**Calculus**

A cubic polynomial function f is defined by f(x) = 4x^3 + ax^2 + bx + k? A cubic polynomial function f is defined by: f(x) = 4x^3 + ax^2 + bx + k where a, b, and k are constants. The function f has a local minimum at x= -1, and the graph of f has a point of inflection at x= -2...

*February 8, 2011*

**Calculus**

Let f be a twice-differentiable function such that f(2)=5 and f(5)=2. Let g be the function given by g(x)= f(f(x)). (a) Explain why there must be a value c for 2 < c < 5 such that f'(c) = -1. (b) Show that g' (2) = g' (5). Use this result to explain why there...

*February 7, 2011*

**Physics**

Is 3 True? or is the answer 9.80?

*February 3, 2011*

**Physics**

So for each of the statements we have to write true or rewrite the part in Caps to make the sentence true. I'm only stuck on a couple. 1. On a position-time graph, the average velocity equals the run MULTIPLIED by the rise. 2. A child drops a ball. The instantaneous ...

*February 3, 2011*

**AP Calculus**

Thank you so much! It makes perfect sense and when I calculated it, it matched up.

*January 26, 2011*

**AP Calculus**

Consider the curve given by x^2+4y^2=7+3xy a) Show that dy/dx=(3y-2x)/(8y-3x) b) Show that there is a point P with x-coordinate 3 at which the line tangent to the curve at P is horizontal. Find the y-coordinate of P. c) Find the value of d^2y/dx^2 (second derivative) at the ...

*January 26, 2011*

**General Chemistry II**

A quantity of ice at 0 degrees celcius is added to 64.3 grams of water in a glass at 55 degrees celcius. After the ice melted, the temperature of the water in the glass was 15 degrees celcius. How much ice was added? The heat of fusion of water is 6.01kJ/mole and the heat of ...

*January 20, 2011*

**Calculus**

Find all points on the graph of f(x)=xe^x at which the tangent line is parallel to the line y-3x=4. i figured out that f'(x)=3 but i don't know what to do with that.

*November 30, 2010*

**Calculus**

Find all points on the graph of f(x)=xe^x at which the tangent line is parallel to the line y-3x=4. i figured out that f'(x)=3 but i don't know what to do with that.

*November 30, 2010*

**Calculus - Still Need Help! Anyone!**

A particle moves along the x-axis with position at time t given by x(t)=e^(-t)sin(t) for 0 is less than or equal to t which is less than or equal to 2 pi. a) Find the time t at which the particle is farthest to the left. Justify your answer I think you have to find the prime ...

*November 29, 2010*

**Calculus!!!!**

A particle moves along the x-axis with position at time t given by x(t)=e^(-t)sin(t) for 0 is less than or equal to t which is less than or equal to 2 pi. a) Find the time t at which the particle is farthest to the left. Justify your answer I think you have to find the prime ...

*November 29, 2010*

**Calculus**

A particle moves along the x-axis with position at time t given by x(t)=e^(-t)sin(t) for 0 is less than or equal to t which is less than or equal to 2 pi. a) Find the time t at which the particle is farthest to the left. Justify your answer I think you have to find the prime ...

*November 29, 2010*

**mumford**

You can do this on a calculator. for y put x-11 and see if its linear. To evaluate just plug 4 for x so it would read f(4)=4-11=-7

*November 29, 2010*

**Calculus**

A particle moves along the x-axis with position at time t given by x(t)=e^(-t)sin(t) for 0 is less than or equal to t which is less than or equal to 2 pi. a) Find the time t at which the particle is farthest to the left. Justify your answer I think you have to find the prime ...

*November 29, 2010*

**Please Help! Calculus**

THANK YOU SO MUCH!

*November 22, 2010*

**Please Help! Calculus**

We have to find out which of these statements are true. I narrowed it down to 2 answers. a) if f"(0)=0, the the graph of f changes concavity at x=0 b) If the function f is continuous on the interval [a,b] and the integral from a to b of f(x)dx=0, then f must have at least...

*November 22, 2010*

**12th Grade Vocabulary**

We have to pick which sentence the vocabulary word is used incorrectly. Vocab Word: Verity a) Many people trusted the VERITY of the accused spies Ethel and Julius Rosenberg, but the defendants were convicted and executed for espionage in 1953. b) Although neutrons and protons ...

*November 21, 2010*

**12th Grade English**

ok here's what my workbook says Circle the letter of the best synonym for the word(s) in bold-faced type. INCUMBENT UPON all officials (incumbent upon is bold-faced.. these are the options a) the parameters of b) the duty of c) the term of office of d) the puissance of e) ...

*November 21, 2010*

**12th Grade English**

We have to find the synonym of the word in bold. I have a few choices but I'm stuck between two.. The words in bold are incumbent upon the phrase reads: incumbent upon all officials Deciding to choose between a) the duty of b) the term of office of

*November 21, 2010*

**algebra**

If your asking the answer to this problem you multiply 6*5=? then divide that by 3

*November 21, 2010*

**12th Grade Calculus**

When a ball is thrown straight down from the top of a tall building, with initial velocity 30 ft/sec, the distance from the release point at time t in seconds is given by s(t)=16t^2+30t. If the release point is 300 ft above ground, what is the velocity of the ball at the time ...

*October 27, 2010*

**Calculus**

When a ball is thrown straight down from the top of a tall building, with initial velocity 30 ft/sec, the distance from the release point at time t in seconds is given by s(t)=16t^2+30t. If the release point is 300 ft above ground, what is the velocity of the ball at the time ...

*October 26, 2010*

**12th grade Calculus**

Thank you so much bobpursley!!!

*October 5, 2010*

**12th grade Calculus**

It says find the numbers, if any, at which the given function is discontinuous. f(x)=abs(x+2) *abs - absolute value f(x)=e^xsinx for both of these problems i saw that it was continuous but i don't really know

*October 5, 2010*

**Calculus**

It says find the numbers, if any, at which the given function is discontinuous. f(x)=abs(x+2) *abs - absolute value f(x)=e^xsinx for both of these problems i saw that it was continuous but i don't really know

*October 5, 2010*

**12th grade**

Factor x^2+x+12 now

*October 5, 2010*

**US Government**

Society operates more efficiently if government power is centralized. What reasons exist for continuing federalism in its current form? In other words, defend a federal system of government.

*October 3, 2010*

**English - Beowulf**

So we just started reading Beowulf at school and we're around ch 8. Our question to answer was Whose account of Beowulf and Brecca's swimming match is more credible/believable and why? This is referring to Unferth's and Beowulf's stories. I said that Beowulf ...

*September 23, 2010*

**College Chemistry**

I got the following, but I'm not sure if I did it correctly: 2Fe(OH)3 + 3OCl- ->2FeO4-2 + 3Cl- + 4H+ + H2O If someone could let me know whether I solved it correctly or not, that'd be nice. :)

*September 23, 2010*

**American Government**

I have to do a 5 minute presentation on George Washington and I have to focus on his contributions towards the Constitution. All the sites I go to have pretty much the same information. Does anyone have sites that could help me?

*September 21, 2010*

**Calculus, need help again...**

If the function f is defined by f(x)=x^2-2x, find limit h->0 (f(3+h)-(f(3-h))/2h

*September 21, 2010*

**Caclulus, bobpursley HELP!**

Sorry for bothering you on this one question but I just replied to my original problem if you could help me with that.

*September 21, 2010*

**Calculus, bobpursley!**

Oh I just replied again.

*September 21, 2010*

**Calculus, bobpursley!**

This has to do with my last Calculus problem. I need help on it..The part I replied to after you answered the question.

*September 21, 2010*

**Calculus**

(f(3+h)-(f(3-h))/2h I put a minus sign because it has a negative in front of the f(3-h) so it's -(f(3-h))

*September 21, 2010*

**Calculus**

Thank you for your help! For the second part I thought it would be -(9+6h-h^2)-6+2h?

*September 21, 2010*

**Calculus**

If the function f is defined by f(x)=x^2-2x, find limit h->0 (f(3+h)-(f(3-h))/2h

*September 21, 2010*

**Calculus..Need Help Soon**

If the solutions of f(x)=0 are 1 and -2, then the solutions of f(2x)=0 are a)1 and 2 b) 1/2 and -1 c) 2 and -4 d)-2 and 4 2)-1/2 and -1

*September 12, 2010*

**Calculus..Need Help Soon**

If f(x)=1-x^3 and f^-1 is the inverse of f, how many solutions does the equation f(x)=f^-1(x) have? a)none b)one c)three d)five e)six

*September 12, 2010*

**Calculus..Need Help Soon**

If x=1 and x=2 are zeros of f(x)=3X^3+Ax^2+Bx+2, then the value of A+B is a)1, b)-1, c)9, d)-9, e) cannot be determined I think it can't be determined but i don't know!

*September 12, 2010*

**Math**

A rational function g has the lines x=2 and x=-2 as vertical asymptotes, the line y=4 as a horizontal asymptote, and numbers 3 and 1 as zeros. Find a formula for g(x). So I got g(x)=(4x^2-16x+12)/(x^2-4) Is this correct

*September 6, 2010*

**Calculus (Reiny or MathMate)**

A rational function g has the lines x=2 and x=-2 as vertical asymptotes, the line y=4 as a horizontal asymptote, and numbers 3 and 1 as zeros. Find a formula for g(x). So I got g(x)=(4x^2-16x+12)/(x^2-4) Is this correct

*September 6, 2010*

**Calculus**

A rational function g has the lines x=2 and x=-2 as vertical asymptotes, the line y=4 as a horizontal asymptote, and numbers 3 and 1 as zeros. Find a formula for g(x). So I got g(x)=(4x^2-16x+12)/(x^2-4) Is this correct Math Mate?

*September 6, 2010*

**Calculus**

ok, so i got e^-7 and e^2 does that mean i reject e^-7 because its less than or equal to 0?

*September 6, 2010*

**Calculus**

Solve for x if 5+lnx=14/lnx.

*September 6, 2010*