Friday
September 19, 2014

Posts by becky


Total # Posts: 505

Calc 3
can you please explain to me where you got the numbers for T(-1,1,2) I know you did the cross product but I can not seem to get the same numbers as you. Please explain
September 27, 2012

Calc 3
Find parametric equations for the tangent line to the curve of intersection of the paraboloid z = x2 + y2 and the ellipsoid 6x2 + 5y2 + 7z2 = 39 at the point (−1, 1, 2)
September 27, 2012

Calc 3
At what point on the paraboloid y = x2 + z2 is the tangent plane parallel to the plane 7x + 2y + 3z = 2? (If an answer does not exist, enter DNE.)
September 27, 2012

Lang Arts
Would #2 be A?
September 25, 2012

physics
Two blocks are connected by a lightweight, flexible cord that passes over a frictionless pulley. If m1 = 3.8 kg and m2 = 9.2 kg, and block 2 is initially at rest 140 cm above the floor, how long does it take block 2 to reach the floor?
September 23, 2012

physics
Two blocks are connected by a lightweight, flexible cord that passes over a frictionless pulley. If m1 = 3.8 kg and m2 = 9.2 kg, and block 2 is initially at rest 140 cm above the floor, how long does it take block 2 to reach the floor?
September 23, 2012

Calc 3
thank you!!!!!!
September 22, 2012

Calc 3
Use the Chain Rule to find ∂z/∂s and ∂z/∂t. z = tan(u/v), u = 7s + 4t, v = 4s − 7t
September 22, 2012

Calc 3
we were not given f(x,y) the whole problem is listed above, apparently there is a link that is supposed to help us but I followed it and don't know what I am doing wrong and I cannot post the link because it is on a special homework website.
September 22, 2012

Calc 3
If z = f(x, y), where x = r^2 + s^2 and y = 8rs, find ∂^2z/(∂r ∂s).
September 22, 2012

calc 3
yes i already got parts a and b i do not know how to do part c sorry i should have specified that in my post
September 21, 2012

calc 3
The length script l, width w, and height h of a box change with time. At a certain instant the dimensions are script l = 7 m and w = h = 5 m, and script l and w are increasing at a rate of 6 m/s while h is decreasing at a rate of 4 m/s. At that instant find the rates at which ...
September 21, 2012

English
1.I started play the oboe because [I've heard] it was a challenging instrument (a) no change (b) I'd have heard (c)I've been hearing (d) I'd heard 2. That was [four years ago and, I've] enjoyed learning to play (f) no change (g) four years ago, and I've...
September 20, 2012

physics
A crate of potatoes of mass 13.0 kg is on a ramp with angle of incline 30° to the horizontal. The coefficients of friction are μs = 0.76 and μk = 0.35. Find the frictional force (magnitude and direction) on the crate if the crate is sliding up the ramp.
September 20, 2012

calc 3
Use the Chain Rule to find dw/dt. w = ln (x^2 + y^2 + z^2)^.5 , x = 9 sin t, y = 6 cos t, z = 7 tan t
September 20, 2012

Calc 3
Find all partial derivatives? v = (xy)/(x-y) vxx= vxy= vyx= vyy=
September 20, 2012

physics
A barge is hauled along a straight-line section of canal by two horses harnessed to tow ropes and walking along the tow paths on either side of the canal. Each horse pulls with a force of 540 N at an angle of 12° with the centerline of the canal. What is the net force on ...
September 19, 2012

calc 3
Find all partial derivatives? v = (xy)/(x-y) vxx= vxy= vyx= vyy=
September 19, 2012

calc 3
Use polar coordinates to find the limit. [If (r, θ) are polar coordinates of the point (x, y) with r ≥ 0, note that r → 0+ as (x, y) → (0, 0).] (If an answer does not exist, enter DNE.) lim (x, y)→(0, 0) [(3e^−x^2− y^2) − 3]/ (x^2...
September 17, 2012

Calc 3
but there is no lHospitals rule in multivariable
September 14, 2012

Calc 3
Find the limit, if it exists. (If an answer does not exist, enter DNE.) lim (x, y)→(0, 0) of (x^2 + y^2)/[((x^2 + y^2 +64)^.5)-8]
September 14, 2012

Calc 3
A cooling tower for a nuclear reactor is to be constructed in the shape of a hyperboloid of one sheet. The diameter at the base is 300 m and the minimum diameter, 500 m above the base, is 200 m. Find an equation describing the shape of the tower in the coordinates where the ...
September 12, 2012

Chemistry
1.42 g/cm^2 to mg/mm^2
September 4, 2012

calc 3
The magnitude of a velocity vector is called speed. Suppose that a wind is blowing from the direction N45°W at a speed of 40 km/h. (This means that the direction from which the wind blows is 45° west of the northerly direction.) A pilot is steering a plane in the ...
August 31, 2012

calc 3
Question Find an equation of the set of all points equidistant from the points A(−2, 5, 2) and B(5, 1, −3).
August 30, 2012

calculus
hi i think i know what you mean already. my answer for F"(v) (-150v^5/2 + 40500v)/v^4 i simplified further, it became (-150v(v^3/2 - 270))/v^4 cancel off the common factor v it became (-150(v^3/2 - 270))/v^3 Am i correct??
August 13, 2012

calculus
based on my question, i retyped... F(v) : (600v^3/2 + 20250)/v F'(v) : (300v^3/2 - 20250)/v^2 F"(v) : (-150v^5/2 + 40500)/v^3 Reiny, isn't your answer suppose to be f(x) = 600 v^(3/2) + 20250 v^-1, instead of f(x) = 600 v^(1/2) + 20250 v^-1 ?? 1/2 power and 3/2 ...
August 13, 2012

calculus
I do not want the simplified answer by the way...I need the answer as an expression only
August 13, 2012

calculus
Ok but the power 5/2 is wrong? Should have been power 3/2? I keep on getting the answer 5/2.. I don't know which part of my working is wrong
August 13, 2012

calculus
Just want to check whether my answer is correct for quotient rule F(v) : (600^3/2 + 20250)/v F'(v) : (300^3/2 - 20250)/v^2 F"(v) : (-150v^5/2 + 40500)/v^3 Can anyone let me know whether my answer is correct for first and second derivative based on F(v) ??
August 13, 2012

calculus
yes it should be, F(v) : (600^3/2 + 20250)/v F'(v) : (300^3/2 - 20250)/v^2 F"(v) : (-150v^5/2 + 40500)/v^3 for F"(v), this is how i get: F'(v) : (300^3/2 - 20250)/v^2 F"(v) : ((300v^3/2 - 20250)' * v^2) - ((300v^3/2 - 20250) * (v^2)')/v^4 F"...
August 13, 2012

calculus
nope, it's not a typo. the 5/2 is the power of 5 over 2. it is not 5 divide by 2. is my above answer correct?
August 13, 2012

calculus
Just want to check whether my answer is correct for quotient rule F(x) : (600^3/2 + 20250)/v F'(x) : (300^3/2 - 20250)/v^2 F"(x) : (-150v^5/2 + 40500)/v^3 Can anyone let me know whether my answer is correct for first and second derivative based on F(x) ?? Thank you!!
August 13, 2012

calculus
A ship uses $( 7v^2 ) of fuel per hour when travelling at a constant speed of v km/h. Other expenses in operating the ship (i.e. crew and equipment) amount to $345 per hour. The ship makes a journey of 100 km. C(v) : (700v^2 + 34500)/v C'(v): (700v^2 - 34500)/v^2 C"(v...
August 13, 2012

calculus
i got the answer!! thank you!!!
August 13, 2012

calculus
pls ignore the above question... to make it clearer for the question, it is... f(x): (700v^2 + 34500)/v f'(x) : (700v^2 -34500)/v^2 f''(x) : ???
August 13, 2012

calculus
The question should be: f(x): 700v^2 + 34500/v f'(x) : 700v^2 -34500/v^2 f''(x) : ???
August 13, 2012

calculus
sorry typo error above, question is, f(x): 700v^2 + 34500/v f'(x) : 700v^2 -34500/v^2 f"'(x) : ???
August 13, 2012

calculus
how to find the second derivative of quotient rule? f(x): 700v^2 + 3450/v f'(x) : 700v^2 -3450/v^2 f"'(x) : ???
August 13, 2012

calculus
The 5 question is asking how many km/h...appreciated if anyone cld help...thank you!!
August 12, 2012

calculus
Hi i need help in this. Some of the parts i got the answer but some i don't. please help! A ship uses $(7v^2) of fuel per hour when travelling at a constant speed of v km/h. Other expenses in operating the ship (i.e. crew and equipment) amount to $345 per hour. The ship ...
August 12, 2012

calculus
i get the answer already! thank you!
August 11, 2012

calculus
Hi thanks for helping. But when differentiate pi^2 isn't that is 2pi? How come your answer is 2pi^2? and when different r^2 isn't that is 2r? How come your equation is dv/dt = 2pi^2 D r + 8/3*pi*r^2? Because my answer is 2pi D 2r + 8/3*pi*r*^2. anyone can explain? Thanks!
August 11, 2012

calculus
A bicycle wheel has a diameter D = 60 cm and the tyre has a cross sectional radius of r = 2.5 cm. The volume V of the inner tube is given by V = pi^2 D r^2 + (8/3*pi*r^3) If air is being pumped into the tyre so that the volume of the inner tube is increasing at the rate of 12 ...
August 11, 2012

math
In a time-use study, 20 randomly selected managers were found to spend a mean of 2.40 hours each day on paperwork. The standard deviation of the 20 scores is 1.30 hours. Also, the sample data appear to have a bell-shaped distribution. Construct the 95% confidence interval for ...
July 29, 2012

statistics
One of the problems with a study such as this one is the small size of the samples. If you wanted to estimate the proportion of a certain color of candy to within 2% of the actual proportion, how many individual pieces of candy must you sample? Assume you want to be 90% ...
July 23, 2012

LIT 210
What do you think Oedipus Rex and A Raisin in the Sun imply about Sophocles’ and Lorraine Hansberry’s cultural identities?
July 20, 2012

Math
thank you!!
June 30, 2012

Math
Im working on a math question and the answer is 2hr and 24min. I am getting 2.4 with my calculations how do i take 2.4 and get 2hr and 24min.???
June 30, 2012

Algebra
Thank you been 8 years and trying to go back to school trying to re learn and or remember thanks a bunch!!!!
June 28, 2012

Algebra
If two planes leave the same airport at 1:00 PM, how many miles apart will they be at 3:00 PM if one travels directly north at 150 mph and the other travels directly west at 200 mph? I understand that d = sqrt[300^2 + 400^2] d = sqrt[250,000] But im not sure how you get 500 ...
June 28, 2012

Finance
Carnation needs to buy a $12,500 part the part company is offering cash discount terms of 4/10, n30. Carnation has a tight cash flow, wants to discount a 180 day note dated February 12 with a maturity value of $10,300. Bank offers a discount rate of 6%. Should carnation ...
June 6, 2012

Physics
Two spherical objects with a mass of 7.60 kg each are placed at a distance of 2.93 m apart. How many electrons need to leave each object so that the net force between them becomes zero?
June 6, 2012

physics
Two small pith balls, each of mass m = 16.6 g, are suspended from the ceiling of the physics lab by 1.8 m long fine strings and are not moving. If the angle which each string makes with the vertical is è = 19°, and the charges on the two balls are equal, what is the...
June 6, 2012

math
pam is offered a salary of 28,000 a year for 30 years with annual raises of 6 % what would be pam's salary during her 5th year on the job
April 26, 2012

Math
The weights of adult long-tongued fruit bats are known to be normally distributed with a mean of 20.22 grams and a standard deviation of 3.23 grams. What is the probability that a randomly selected bat will: a) weigh at most 15 grams? b) weigh less than 30 grams?
March 23, 2012

math
The weights of adult long-tongued fruit bats are known to be normally distributed with a mean of 20.22 grams and a standard deviation of 3.23 grams. What is the probability that a randomly selected bat will: a) weigh at most 15 grams? b) weigh less than 30 grams?
March 21, 2012

Physics
wow I thought this was a homework help site. Not a be rude to someone you don't even know site? I have read the book thanks but physics is a hard topic to understand. You wasted your own time by commenting that rude comment. Thanks bye x
March 21, 2012

Physics
Tim and Ray have the same mass and they both climb up the same hill. Tim climbs the hill in 12 minutes and Ray in 22 minutes. a) Who does more work? b) Who develops the most power?
March 21, 2012

Physics
A blue whale materializes 11.5 km above an airless planet with an acceleration of gravity of 6.85 m/s2. What is the speed of the whale right before impact? (Work-Energy Theorem)
March 21, 2012

Physics
A car is driven at a constant speed of 85 km/h down a road. The car's engine delivers 49.2 kW of power. Calculate the average force that is resisting the motion of the car.
March 21, 2012

Physics
Michelle pulls a 14.5 kg wheeled cart with a rope along a flat road. The rope makes a 28.0 degree angle with the horizontal. If the tension in the rope is 350 N and she pulls the cart 56.7m how much work does Michelle do?
March 21, 2012

Physics
Bryant is fired from a cannon with an initial speed of 14 m/s. If his mass is 80 kg what is his initial kinetic energy?
March 21, 2012

Physics
A ball is moving at 82 m/s when it hits a ball at rest which has a mass fours times as big as its own. The formally stationary ball leaves the collision with a speed of 7.5 m/s what is the final velocity of the first ball?
March 21, 2012

physics
Neona is on a tricycle A, combined mass 62 kg, and Alyssia is on tricycle B, combined mass 54 kg. They are initially at rest, but they push off of each other. What is Neona's speed immediately after the push if Alyssia's is 4.2 m/s?
March 21, 2012

Physics
Kenya finally loses her cool and punches her teacher. The teacher weighs 85 kg. He sees the punch coming and begins to back up at a speed of 0.60 m/s. After Kenya clocks him, he is moving backwards at a speed of 0.82 m/s. If the contact time of Kenya's fist to the teachers...
March 21, 2012

Physics
Two trucks that appear to be identical collide on an icy road. One was originally at rest. The trucks stick together and move off at more than half the original speed of the moving truck. What can you conclude about the contents of the two trucks?
March 21, 2012

Physics
You are sitting at a baseball game when a foul ball comes in your direction. You prepare to catch it barehanded. In order to catch it safely, should you move your hands toward the ball, hold them still, or move them in the same direction as the moving ball? Explain.
March 21, 2012

Physics
As you lift a chair to store is upside down on a desk, gravity exerts a force, mg, downward and you exert a force of the same magnitude upwards. The two forces are equal in magnitude and opposite in direction. From this is would appear that no work was done, but you know you ...
March 21, 2012

Physics
Roads seldom go straight up a mountain, they wind back and forth. Explain why this is useful
March 21, 2012

math
6+10+6+7+6=35
March 7, 2012

math
i have 3 numbers 10,7,and 6 and need to make them work in 35...but it cant be like 7 into 35 it has to be all 3 numbers and can be used more than once but after another number like 10 + 7 +10 ect
March 7, 2012

Math
circumference (the crust)= 3.14(pie)*radius^2 C=3.14*12^2 (12 inch) = 452.16 C=3.14*8^2 (8 inch)=200.96 452.16 minus 200.96 = 251.2 in in diameter
March 6, 2012

physics
Determine the velocity of a satellite orbiting Earth at a height of 3.2 x 10^3 meters.
March 1, 2012

physics
Jessica, who mass is 55 kg, is 3.50 meters away from a 0.20 kg bag of Fig Newtons. What is the gravitational force between Jessica and the cookies?
March 1, 2012

physics
Imagine a planet that orbited the sun at a distance three times that of Earth. What would the period of that planet be in Earth years?
March 1, 2012

physics
A car is rounding a curve with a radius of 12.0 m at 8.2 m/s when it hits a slippery patch. What is the minimum coefficient of static friction between the car and the slick patch of road that will allow the car to round the corner safely?
March 1, 2012

physics
Someone swints a 3.0 kg mass at the end of a 2.3 m string in a horizontal circle. If the string can withstand a tension of 80 N, at what speed can they swing the mass before they risk a lawsuit?
March 1, 2012

Thermodynamics
Consider a system consisting of two glass bulbs, each with volume V, and each containing n moles of gas. Bulb A contains nA moles of A and bulb B contains nB moles of B (a different gas), nA = nB. The bulbs are connected by a closed stopcock. The stopcock is opened so that the...
February 22, 2012

physics
In a water balloon toss a contestant throws her balloon with a speed of 4.84 m/s at an angle of 16.5 degrees above the horizontal. Find the maximum height, the time of flight and the range of the balloon assuming her partner catches the balloon at the same height at which it ...
February 6, 2012

physics
A man is using a bow and arrow for the first time of his life. He is 25 meters from the target and aims directly at the center of the target. Surprisingly the arrow leaves the bow with a velocity of 54 m/s directly towards the center of the target and initially the velocity is...
February 6, 2012

physics
Many professional golfers can hit a golf ball 300 meters with a driver. The face of a driver and the swing pattern causes the ball to leave the club at around 18 degrees from the horizontal. Assuming the ball travels exactly 300 meters in the air before it bounces the first ...
February 6, 2012

physics
a mass being held by a string moves with speed v on a circular path of radius r, and has a period of revolution T. if it was desired to travel one revolution in twice as much time as before, what would be the radius of the path? what if the time was halved?
January 22, 2012

AP Statistics
Nurse practitioners are nurses with advanced qualifications who often act much like primary care physicians. Medical researchers wnat to design a study to compare the effectiveness of nurse practitioners and physicians. They recruit 1200 volunteer subjects for the tudy, each ...
December 16, 2011

geometry
35
December 11, 2011

ALGEBRA
Suppose you have a $1,000 charge on a credit card charging 1% monthly interest using the adjusted balance method. The minimum payment due in May is $70. How much will you save in interest charges in June by paying $140 instead?.
November 26, 2011

microeconomics
if the price elasticity of demand for a cup of tea is equal to 3, how would you interpret this result?
November 17, 2011

Calculus
You are the owner of a delivery company with one truck. The trucks fuel economy is 1200/x miles per gallon when driving at x miles per hour (where 80 >= x <= 110). The price of fuel is $1 per gallon. You pay the truck driver $8 per hour. If a delivery 100 miles away is ...
November 17, 2011

Calculus
OH NEVER MIND! I GOT IT HAHAHA!
November 6, 2011

Calculus
Oh i shoud've been more specific, what i meant to ask was how do you find xa, ya etc. at 1/2 hours? Thanks in advance! :)
November 6, 2011

Calculus
THANKS FOR ALL THE HELP! One question, how do you find xa,ya, xb, and yb?
November 6, 2011

Calculus
At 1:00 p.m. ship A is 25 km due north of ship B. If ship A is sailing west at a rate of 16km/h and ship B is sailing south at 20km/h, find the rate at which the distance between the two ships is changing at 1:30 p.m.
November 6, 2011

chemistry
.115 mol of solute is put in a container and water is added to give 250ml of solutrion. what is the molarity
November 4, 2011

Calculus
For question a), how did you get 12800? Where'd that come from?
November 1, 2011

statistics
What is the standard deviation of a normal distribution, whose mean is 35, in which an x-value of 23 has a z-score of -1.63?
October 13, 2011

College Physics
In this problem you will estimate the heat lost by a typical house, assuming that the temperature inside is T(in) = 20 degrees celcius and the temperature outside is T(out) = 0 degrees celcius. The walls have fiberglass insulation, which dominates the heat conduction ...
October 8, 2011

College Physics
The top layer of your goose down sleeping bag has a thickness of 5.0 cm and a surface area of 1.0 m^2. When the outside temperature is -18 degrees celcius you lose 24 Cal/hr by heat conduction through the bag (which remains at a cozy 34 degrees celcius inside). Assume that you...
October 7, 2011

College Physics
the answer is 0.027
October 7, 2011

College Physics
is k 0.023076923 ?
October 7, 2011

College Physics
The top layer of your goose down sleeping bag has a thickness of 5.0 cm and a surface area of 1.0 m^2. When the outside temperature is -18 degrees celcius you lose 24 Cal/hr by heat conduction through the bag (which remains at a cozy 34 degrees celcius inside). Assume that you...
October 7, 2011

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