Saturday

May 23, 2015

May 23, 2015

**Calculus**

A 13 foot ladder is leaning against the house when it's base starts to slide away. By the time is 12 feet from the house the base is moving at the rate of 5 ft/sec. 1.How fast is the top of the ladder sliding down the wall at that moment? 2. At what rate is the angle theta...
*Thursday, October 16, 2014 at 8:26am*

**calculus**

Find the maximum and minimum values of f(x, y) = xy on the ellipse 8\!x^{2} + y^{2} = 9.
*Thursday, October 16, 2014 at 12:36am*

**calculus**

Find the center of mass in the 1st quadrant of the circle x^2+y^2=4 where rho(x,y)=k(x^2+y^2) Thanks.
*Wednesday, October 15, 2014 at 8:14pm*

**REALLY HARD CALCULUS PROBLEMMMM PLEASE HELP ME???**

A circular swimming pool has a diameter of 16 m, the sides are 3 m high, and the depth of the water is 2.5 m. How much work (in Joules) is required to pump all of the water over the side? (The acceleration due to gravity is 9.8 m/s 2 and the density of water is 1000 kg/m 3 .) ...
*Wednesday, October 15, 2014 at 4:31pm*

**Integral Calculus**

A force of 4 pounds is required to hold a spring stretched 0.1 feet beyond its natural length. How much work (in foot-pounds) is done in stretching the spring from its natural length to 0.6 feet beyond its natural length?
*Wednesday, October 15, 2014 at 4:28pm*

**calculus**

Use iterated integral to find the area enclosed by r=2sin2(theta). How do i graph this?
*Wednesday, October 15, 2014 at 12:15pm*

**Calculus problem (PLEASE HELP!!)**

The diameter of a human pupil in millimetres is given by D= (2 + 4x^-0.3) / (1 + x^-0.3) where x is the luminance measured in candelas per square metre. Using this function,what is the diameter of the pupil when there is no light? What happens to the diameter of the pupil as ...
*Wednesday, October 15, 2014 at 9:02am*

**Calculus (Need help)**

Not sure how do do this. Please help? Find all values of a and b so that the function is continuous for all x E R. f(x)= −3a + 4(x^5)b x ≤ −1 { ax − 2b −1 < x < 1 3x^2 − bx + a x ≥ 1
*Wednesday, October 15, 2014 at 7:21am*

**Calculus I**

lim x→ ∞ of e^(−x) sin√x A little lost. Help would be appreciated.
*Wednesday, October 15, 2014 at 5:49am*

**pre-calculus**

You are given a pair of equations, one representing a supply curve and the other representing a demand curve, where p is the unit price for x items. -45 x^2 - 74.5199999999995 x + 15921.36 - 1224.72 p = 0 and 54 x^2 + 1743.12 x + 13880.16 - 6940.08 p = 0 a. Identify which is ...
*Tuesday, October 14, 2014 at 10:01pm*

**pre-calculus**

It has been found that the supply of lamps varies linearly with its price. When the price per item was $ 94.67 ,64 items are supplied; When the price was $ 134.67 , 124 items are supplied. How many lamps are supplied when the price per item is $ 118.00 ? What is the lowest ...
*Tuesday, October 14, 2014 at 9:58pm*

**Calculus**

Find all values of a and b so that the following function is continuous for all x ∈ R. f(x) = −3a + 4x^5(b) x ≤ −1 ax − 2b −1 < x < 1 3x^2 − bx + a x ≥ 1
*Tuesday, October 14, 2014 at 6:32pm*

**calculus**

The half-life of Radium-223 is 11.43 days. If a sample has a mass of 400 mg, find the mass (in mg) that remains after 6 days
*Tuesday, October 14, 2014 at 4:04pm*

**Foundations and Pre-Calculus Math 10**

Find the radius of a cone with a height of 3m and a volume of 30m cubed. So far I have 90m cubed / 3m = pi(r^)3m/3m. Then I get stuck. Help! I'm really bad at math. ):
*Tuesday, October 14, 2014 at 1:30pm*

**pre-calculus**

The Hotel Florence has 550 rooms. Currently the hotel is filled . The daily rental is $ 700 per room. For every $ 14 increase in rent the demand for rooms decreases by 7 rooms. Let x = the number of $ 14 increases that can be made. What should x be so as to maximize the ...
*Monday, October 13, 2014 at 10:51pm*

**calculus**

Use diferenciales para estimar la cantidad de estaño en una lata cerrada de este metal con diámetro de 8 cm y altura de 12 cm, si el estaño tiene 0.004 cm de grosor.
*Monday, October 13, 2014 at 7:12pm*

**Pre-calculus**

You are given a pair of equations, one representing a supply curve and the other representing a demand curve, where p is the unit price for x items. 80 p + x - 380 = 0 and 84 p - x - 40 = 0 Identify which is the supply curve and demand curve and the appropriate domain. Put the...
*Monday, October 13, 2014 at 6:23pm*

**calculus**

Find the dimensions of the rectangular box having the largest volume and surface area 60 square units
*Sunday, October 12, 2014 at 6:49pm*

**Calculus**

Gravel is being dumped from a conveyor belt at a rate of 25 ft3/min, and its coarseness is such that it forms a pile in the shape of a cone whose base diameter and height are always equal. How fast is the height of the pile increasing when the pile is 6 ft high? (Round your ...
*Sunday, October 12, 2014 at 6:25pm*

**calculus**

The volume of a cube is increased from 729 cubic centimetres to 849.285 cubic centimetres. Use differentials to determine: a) by approximately how many centimetres the side length of the cube increases ? B) by approximately how many square centimetres does the surface area of ...
*Sunday, October 12, 2014 at 3:18pm*

**Calculus**

A water trough is 9 m long and has a cross-section in the shape of an isosceles trapezoid that is 40 cm wide at the bottom, 80 cm wide at the top, and has height 40 cm. If the trough is being filled with water at the rate of 0.3 m3/min how fast is the water level rising when ...
*Sunday, October 12, 2014 at 2:21pm*

**calculus**

use differentials to determine by approximately how many square centimeters does the area of a square table increase if its diagonal is increased from 4 centimeters to 4.092 centimeters the question is The area of table increases by approximately (??) square centimetres
*Saturday, October 11, 2014 at 5:52pm*

**statistics**

On this semesters final exam, john scored 72 on his calculus exam and 53 on his statistics exam. The z score for both exams was the same. Which on would he do better on? a. calculus b.statistics c. the exam scores are equivalent
*Saturday, October 11, 2014 at 5:52pm*

**Calculus**

The volume of a cube is increased from 729 cubic centimetres to 849.285 cubic centimetres Use differentials to determine : (a) by approximately how many centimetres does the side length of the cube increase? (b)by approximately how many centimetres does the surface area of the...
*Saturday, October 11, 2014 at 3:50pm*

**calculus**

the surface area of a cube is increased from 24 square centimeters to 26.016 square centimeters . use differentials to determine: (1) by approximately how many centimeters does the side length of the cube increase? (2) by approximately how many cubic centimeters does the ...
*Saturday, October 11, 2014 at 2:55pm*

**statistics**

On this semesters final exam, john scored 72 on his calculus exam and 53 on his statistics exam. The z score for both exams was the same. Which on would he do better on? a. calculus b.statistics c. the exam scores are equivalent
*Friday, October 10, 2014 at 8:17pm*

**calculus**

Verify the given linear approximation at a = 0. Then determine the values of x for which the linear approximation is accurate to within 0.1. (Enter your answer using interval notation. Round your answer to two decimal places.) tan x ≈ x
*Friday, October 10, 2014 at 6:20pm*

**pre-calculus**

You are given a pair of equations, one representing a supply curve and the other representing a demand curve, where p is the unit price for x items. 80 p + x - 380 = 0 and 84 p - x - 40 = 0 a. Identify which is the supply curve and demand curve and the appropriate domain. Put ...
*Friday, October 10, 2014 at 5:06pm*

**economics **

First,label the following scenarios as to whether they would create a producer or consumer surplus. Then, after you have labeled each scenario, calculate the ensuing surplus. Claire is trying to sell her used calculus textbook online. She asks for $150 or best offer and is ...
*Friday, October 10, 2014 at 11:09am*

**calculus**

f(x,y)=2xe^y-3ye^-x derive second order
*Friday, October 10, 2014 at 1:07am*

**Calculus **

Would you please check my answer to make sure I did it right? Bus travel, a bus company finds that monthly costs for one particular year were given by C(t) = 100 + t^2 dollars after t months. After t months the company had P(t) =1000 +t^2 passengers per month. How fast is its...
*Thursday, October 9, 2014 at 5:19pm*

**pre calculus**

sinB + cosB cotB = cscB
*Thursday, October 9, 2014 at 9:28am*

**Calculus**

Some cowboys plan to build a rectangular corral in a canyon. They have 500 feet of fencing to use for three sides of the rectangle (the canyon wall is used for the 4th side). a) What is the maximum area that they can fence in? b) What are the dimensions of the rectangle?
*Wednesday, October 8, 2014 at 8:33pm*

**statistics**

Correction On this semesters final exam, john scored 72 on his calculus exam, (class distribution (u=65, \?=3.57)\) ) and 53 on his statistics exam (class distribution :u=49, ?=2.04. Which exam should he get the better grade. z1=72-65/3.57=1.960 Z2=53-49/2.04=1.960
*Wednesday, October 8, 2014 at 8:11pm*

**statistics**

On this semesters final exam, john scored 72 on his calculus exam, (class distribution (u=65, \?=3.57)\) ) and 53 on his statistics exam (class distribution :u=49, ?=2.04. Which exam should he get the better grade. z1=72-65/3.57=1.960 Z2=53-49/3.57=1.120
*Wednesday, October 8, 2014 at 8:03pm*

**Calculus I**

cos(2x)−cos(x) = -((sin^2)x + 1/4) Need help solving.
*Wednesday, October 8, 2014 at 11:38am*

**CALCULUS HELP NEEDED ASAP!**

Having a lot of trouble with this one: Q) Tidal volume is the volume of air displaced in the lungs between inhalation and exhalation (the amount of air in a breath). The residual volume is given by the remaining in the lungs even after the deepest exhalation (ie the minimum ...
*Wednesday, October 8, 2014 at 11:36am*

**pre-calculus**

A machine worth $10,000 new and having a scrap value of $1000 is to be depreciated linearly over an 18-year life. What will be the value of the machine after 9 years?
*Tuesday, October 7, 2014 at 11:03pm*

**calculus**

An airplane flys at a constant altitude of 2 miles and a constant speed of 600 miles per hour on a straight course that will take it directly over a kangaroo on the ground. How fast is the angle of elevation of the kangaroo's line of sight increasing when the distance from...
*Tuesday, October 7, 2014 at 10:09pm*

**Statistics**

On this semesters final exam, john scored 72 on his calculus exam, (class distribution (u=65, \σ=3.57)\) ) and 53 on his statistics exam (class distribution :u=49, σ=2.04. Which exam should he get the better grade. z1=72-65/3.57=1.960 Z2=53-49/3.57=1.120
*Tuesday, October 7, 2014 at 9:48pm*

**Calculus Please Help!**

Not sure how to do this. Asked before but it was hard to type out the symbols in the equation, so I have a screenshot below. exactly Please help! s.yimg(.)com/hd/answers/i/36cad89caaff4061bf38ed04166cbd76_A.png?a=answers&mr=0&x=1412733166&s=...
*Tuesday, October 7, 2014 at 7:54pm*

**Calculus question**

It looks very complicated and I do not know how to even start. Any help would be immensely appreciated. A pendulum has a mass, m, suspended from a rod of length L. At the time t = 0, the pendulum is pulled through an angle θ0 > 0 to the right and given an initial ...
*Tuesday, October 7, 2014 at 6:55pm*

**Calculus**

An airplane flys at a constant altitude of 2 miles and a constant speed of 600 miles per hour on a straight course that will take it directly over a kangaroo on the ground. How fast is the angle of elevation of the kangaroo's line of sight increasing when the distance from...
*Tuesday, October 7, 2014 at 6:46pm*

**Calculus help please**

I have to evaluate the following: tan((sin^-1)(2/7)) and sin^-1 (sin(17pi/6)) Please help.
*Tuesday, October 7, 2014 at 6:44pm*

**Calculus**

slope of tan line to the ellipse is -4x/y for x^(2)/4+y^(2)/16 Are there any points where the slope is not defined? (Enter them as comma-separated ordered-pairs, e.g., (1,3), (-2,5). Enter none if there are no such points.) slope is undefined at
*Tuesday, October 7, 2014 at 5:05pm*

**calculus 1**

Suppose that a person’s blood pressure at time t in seconds is given by p(t) = 100 + 18 sin (7t). (a) During each heartbeat, what is the systolic pressure (maximum blood pressure) and the diastolic pressure (minimum blood pressure)? (b) According to this model, how many ...
*Tuesday, October 7, 2014 at 3:17pm*

**Calculus**

Simplify the expression cot (cos−1(x)). Not sure how to do this.
*Tuesday, October 7, 2014 at 3:12pm*

**calculus**

Find the slope of the tangent line to the curve (2x+4y)^1/2+(2xy)^1/2=13.4 at the point (6,5).
*Tuesday, October 7, 2014 at 11:43am*

**Calculus**

Suppose that two boats leave a dock at different times. One heads due north, the other due east. Find the rate at which the distance between the boats is changing when the first boat is 56 miles from the dock traveling at a speed of 35 miles per hour and the second boat is 20 ...
*Tuesday, October 7, 2014 at 11:36am*

**AP Calculus**

Using the definition of derivative find f'(x) when f(x) = (1/sqr x) + x.
*Tuesday, October 7, 2014 at 9:34am*

**Physics**

A pistol is shot upwards at an angle of 37 degrees above horizontal, with an initial velocity of 375m/s. What height does it reach? What is its horizontal range? (I pretty much know what formulas to use, but I'm not quite sure HOW to use them.. Also you should know that ...
*Monday, October 6, 2014 at 11:57pm*

**Pre Calculus**

Using Descartes' Rule of Signs how can you determine the number of positive and negative zeros (roots) a polynomial may have?
*Monday, October 6, 2014 at 7:05pm*

**Pre Calculus **

If f(x)=-4x^3 +5x^2 +8 and c=-2 is c a factor of x?(Use the Factor Theorem)
*Monday, October 6, 2014 at 5:41pm*

**Calculus**

A light is hung 15 ft above a straight horizontal path. If a man 6 ft tall is walking away from the light at the rate of 5 ft/sec, how fast is his shadow lengthening and at what rate is the tip of the man’s shadow moving?
*Monday, October 6, 2014 at 10:48am*

**Timerate problem(calculus)**

Sand is being dropped at the rate 10 metercube/min onto a conical pile. If the height of the pile is always twice the base radius, at what rate is the increasing when the pile is 8 m high?
*Monday, October 6, 2014 at 10:46am*

**calculus **

How to solve by completing the square? 1. 4(c+3)^2=1/4 2. (2p-5)^2=1/4 3. 2w^2-3w-3=0
*Monday, October 6, 2014 at 12:54am*

**Calculus**

let F(x) = f(2x) and suppose that the derivative of F(x) = x^(2). Find the derivative of f(2x).
*Sunday, October 5, 2014 at 11:46pm*

**Calculus**

So here is the question: Find and equation of the tangent line to the graph: 4)f(x)=e^(2x) passing through the point (0,0) I find derivative being f'(x) =2e^(2x) Then m = f'(0) = 2 put into point slope formula: (y-y1)=m(x-x1) y-0 = 2(x-0) which comes out to y=2x 0=2x...
*Sunday, October 5, 2014 at 10:27pm*

**calculus**

Implicit diff. y^2 + 4xy +4y^2=40 2yy'+ _______ + 8y*y=0 I am confused with the 4xy. Would you write this out to be 4x*y'+4y OR 4x*4y' + 4y*4x'? Please help
*Sunday, October 5, 2014 at 3:46pm*

**Calculus**

Integrate sqrt(x^2 + x) dx I have completed the squares and got x^2-x = (x+1/2)^2 -1/4 Now i dont know how to proceed, plz help me!
*Sunday, October 5, 2014 at 3:42am*

**Calculus**

I have y = sin^2(3^(x)) which I rewrite as y = (sin(3^(x)))^2 I got the derivative using the chain rule as the following y' = 3(sin(3^x))^2 (cos(3x)) (3^(x)(ln(3)) Can anyone confirm whether this is right/wrong? Thanks
*Sunday, October 5, 2014 at 12:40am*

**Calculus**

Find the equation of the tangent to the curve y=3x^2+4x which makes a 45 degree angle with the negative x-axis
*Saturday, October 4, 2014 at 6:48pm*

**pre-calculus**

It has been discovered in a certain state that the relationship between the number of snow shovels demanded varies linearly with its price. When the price per item was $ 38 ,2200 items were demanded; When the price was $ 49 , 2125 items were demanded. Determine the price per ...
*Friday, October 3, 2014 at 9:40pm*

**Calculus **

Find all values of x if any where the tangent line to the graph of the given equation is horizontal? y= x - sqrt (x) I am very confused would I work it like this? y = x - x^-1/2 then set x = 0? Please explain. thank you!
*Thursday, October 2, 2014 at 11:45pm*

**pre calculus**

Use Hooke's Law for springs, which states that the distance a spring is stretched (or compressed) varies directly as the force on the spring. A force of 265 newtons stretches a spring 0.15 meter. (a) What force is required to stretch the spring 0.2 meter? (Round your ...
*Thursday, October 2, 2014 at 7:46pm*

**Calculus**

True or false: a) if f(x) is continuous at a, then the limit of f(x) as x approaches a exists b) if the limit of f(x) as x approaches a exists, then f(x) is continuous at a My answer: a) false b) true
*Thursday, October 2, 2014 at 7:33pm*

**calculus**

Find the volume of the solid obtained by rotating the region bounded by the given curves about the specified axis. x+y=4,x=5−(y−1) 2 ;
*Wednesday, October 1, 2014 at 11:38pm*

**Stat**

Thirty randomly selected students took the calculus final. If the sample mean was 89 and the standard deviation was 6.2, construct a 99% confidence interval of the mean score of all students. Assume that the population has a normal distribution
*Wednesday, October 1, 2014 at 4:46pm*

**Pre-Calculus/Trig...**

Help Please For the function defined by: f(x)= (x^2,x≤1) (2x+1,x>1) Define f(0). and also how would i graph f(x)?
*Wednesday, October 1, 2014 at 11:06am*

**Pre Calculus**

e^-x sqrt(3e^2x -5/4) = e^x No idea how to approach this.
*Wednesday, October 1, 2014 at 6:55am*

**Calculus**

Hi. I need help with finding the derivative of the function: y= [(sec^7 x)/7] - [(sec^5 x)/5] Thanks!
*Tuesday, September 30, 2014 at 9:38pm*

**Calculus**

Hi! I need help finding the derivative of this function. f(x)= ln [(x(x-1))/(x-2)] Thank you.
*Tuesday, September 30, 2014 at 9:05pm*

**Pre-Calculus/Trigonometry**

Express the following function, F(x) as a composition of two functions and f and g. f(x)= x^2/(x^2+4)
*Tuesday, September 30, 2014 at 4:29pm*

**Pre-Calculus/Trigonometry**

For the sequence an = 4n + 5: find: the first five terms: find the sum of the first 25 terms: is it a arithmetic sequence? If so how can you tell, if not, why not?
*Tuesday, September 30, 2014 at 4:20pm*

**Pre-Calculus/Trigonometry**

Solve the following system of equations algebraically. Verify the solution by using matrices. 8x-2y=5 -12x+3y=7
*Tuesday, September 30, 2014 at 1:23pm*

**Pre-Calculus/Trigonometry**

For f(x)= 1/(x-5) and g(x)= x^2+2, find: a. (f o g)(x) b. (g o f)(6)
*Tuesday, September 30, 2014 at 12:58pm*

**Stat**

Thirty randomly selected students took the calculus final. If the sample mean was 89 and the standard deviation was 6.2, construct a 99% confidence interval of the mean score of all students. Assume that the population has a normal distribution. what formula do i use????
*Tuesday, September 30, 2014 at 12:36pm*

**Pre-Calculus/Trigonometry**

for f(x)= 1/(x^2-3), find: a. f(3) b.f(2+h)
*Tuesday, September 30, 2014 at 12:01pm*

**Pre-Calculus/Trigonometry**

Solve the following system of equations algebraically. Verify your solution by using matrices. 3x-y=0 5x+2y=22
*Monday, September 29, 2014 at 7:22pm*

**Calculus**

Solve the following e^-x (square root((3e^2x) - 5/4)) = e^x
*Monday, September 29, 2014 at 6:58pm*

**Pre-Calculus/Trigonometry**

give an example of an arithmetic sequence also give an example of a system of equations with no solutions
*Monday, September 29, 2014 at 5:42pm*

**Pre-Calculus/Trignometry**

am i right? for f(x)=2x+1 and g(x)=x^2-7 find (fog)(x. 2x^2-13 <--
*Monday, September 29, 2014 at 4:24pm*

**Pre-Calculus/Trignometry**

Give an example of a function whose domain is [2,infinity).
*Monday, September 29, 2014 at 4:09pm*

**Calculus**

r=log(cos^2(4theta)) what is the derivative of this?
*Monday, September 29, 2014 at 10:24am*

**Calculus**

What is the derivative of y=2^x?
*Sunday, September 28, 2014 at 8:17pm*

**CALCULUS**

I need to find the unit normal vector given: r(t)= ti + (6/t) j where t= 3 I know I need to find the unit tangent vector first, which is r'(t) divided by the magnitude of r'(t). r(t) can be rewritten as ti+ 6t^-1 r'(t) = i- 6t^-2 = i- [6/ (t^2)] j For the magnitude...
*Sunday, September 28, 2014 at 4:21pm*

**Calculus Minima Problems**

A small island is 2 km off shore in a large lake .A woman on the island can row her boat 10 km/hr and can run at a speed of 20 km/hr. If she rows to the closest point of the straight shore, she will land 6 km from a village on the shore. Where should she land to reach the ...
*Sunday, September 28, 2014 at 12:32pm*

**Calculus Maxima/Minima**

An automobile traveling at the rate of 30 ft/sec is approaching an intersection. When the automobile is 120 ft. from the intersection, a truck, traveling at the rate of 40 ft/sec on a road at right angles with the automobile’s road crosses the intersection. How long after...
*Sunday, September 28, 2014 at 11:30am*

**Calculus**

A small island is 2 km off shore in a large lake .A woman on the island can row her boat 10 km/hr and can run at a speed of 20 km/hr. If she rows to the closest point of the straight shore, she will land 6 km from a village on the shore. Where should she land to reach the ...
*Sunday, September 28, 2014 at 11:29am*

**Pre-Calculus**

1.) Find (f - g)(x) if f(x) = 2x - 5 and g(x) = 4. 2.) Given f(x) = 4 and g(x) = 2x - 1, find (f - g)(x). Thanks so much! :)
*Sunday, September 28, 2014 at 8:35am*

**Calculus**

Hello, my question is the following: The derivative of f(x) = ln(x) is given by f'(x) = 1/x. Find an equation of the tangent line to the graph y = ln(x) that passes through the point (0,0). So if I go through this using the typical method I use I have the point slope ...
*Saturday, September 27, 2014 at 7:04pm*

**Calculus**

2. The slope of the tangent line to the graph of the exponential function y=2^x at the point (0,1) is the limit of (2^x-1)/x as x approaches 0. Estimate the slope to three decimal places. My work: (-1,0.5) (-0.5,0.586) (-0.9,0.516) (-0.999,0.5) (0,empty) (0.0001, 0.693) (0.001...
*Friday, September 26, 2014 at 7:35pm*

**Calculus**

1. Evaluate the function at the given numbers (correct to six decimals places). Use the results to guess the value of the limit,or explain why it does not exist. F(t)=( t^(1/3) - 1)/(t^(1/2) - 1) ; t= 1.5,1.2,1.1,1.01,1.001; The limit of F(t) as t approaches 1. My work: t=1....
*Friday, September 26, 2014 at 5:25pm*

**Pre-Calculus**

Help please If f(x)=8x and g(x)=2x+1 find (fog)(x) 16x^2+8x 16x+1 16x+8 10x+1
*Friday, September 26, 2014 at 5:02pm*

**Pre-Calculus**

Help Please Solve the following system of equations. Round your answers to the nearest tenth. Your answer will be in the form: (M,N). Find M + N, rounded to the nearest tenth. 5x+2y=7 -2x+6y=9
*Friday, September 26, 2014 at 11:46am*

**Pre-Calculus**

Hello! I need help with these 2 questions: 1.) Describe how the graphs of f(x) = |2x| and g(x) = -|2x| are related. a.) All of these. b.) The graph of g(x) is a reflection of the graph of f(x) over the y-axis. c.) Non of these. d.) The graph of g(x) is a reflection of the ...
*Friday, September 26, 2014 at 8:19am*

**Calculus**

A man standing 9 feet from the base of a lamppost casts a shadow 6 feet long. If the man is 6 feet tall and walks away from the lamppost at a speed of 30 feet per minute, at what rate, in feet per minute, will his shadow lengthen?
*Thursday, September 25, 2014 at 11:55pm*

**calculus 1**

a ladder 20 ft. long rests against a vertical wall.If the bottom of a ladder slides away from the wall at a rate of 4 ft./sec, how fast is the top of the ladder sliding down the wall when the bottom of the ladder is 12 ft. from the wall? x^2 +y^2 = 20^2 x^2 + y^2 = 400 ...
*Thursday, September 25, 2014 at 9:57pm*

**Calculus **

I am so lost, I have no idea what to do next. Find the equation of the tangent line to the graph at the indicated point f(x) =x^2 +x ; a=-1 I started out using f(-1)= (-1+h)-(-1)/h but i am so lost on what to do next. I have tried to look at examples in the book, but i do not ...
*Thursday, September 25, 2014 at 6:29pm*

**Calculus**

It is known that the quantity demanded of a certain make of portable hair dryer is x hundred units/week and the corresponding wholesale price is shown below where p is in dollars. p = sqrt(225 - 5x) The supplier will make x hundred units of hair dryers available in the market ...
*Thursday, September 25, 2014 at 2:09am*