# Posts by Julie

Total # Posts: 1,165

Calculus
A smoke detector contains 0.2 mg of Americium 241 (Am-241), a radioactive element that decays in t years according to the relation m = 0.2(0.5)^(t/432.2). Where m is the mass, in milligrams, remaining after t years. A) The smoke detector will no longer work when the amount of ...

Thank you Damon!

Determine the equation of the tangent line to the function f(x) = x + Sinx at x = pie

In part c) for xcosx could you simplify that or do you keep it as xcosx? Thanks

The answer for b) is e^-4(2x) ? And everything after that is for c) right. So the final answer for c) would be xe^sinx(xcosx + 2) ? Thankyou.

Could you help me for these two: b) y = (x²+1)e^-4 c) y = x²(e^Sinx) Please & Thank you.

Determine the derivative of each function A1) y = e^x(Sin²x) A2) y = e²Sin²x B1) y = (x³ + 1)e^-2 B2) y = (x² + 1)e^-2 C) y = x²(theta^Sinx)

Calculus
The voltage signal from a standard european wall socket can be described by the equation V(t) = 325Sin100(pie)t, where t is time in seconds and v is voltage at time t A) find the maximum and minimum voltage levels and times at which they occur B) determine i) the petiod, T, in...

Calculus
Determine derivative of each function A) y = 3xSinx B) f(t) = 2t^2Cos2t C) [(pie)tSin](pie(t)-6)

Calculus
A) y'= 2sin(2x) B) y'= 4sin(2theta) -2cos(2theta) C) y'= 2piCos(2theta)

Calculus
Differentiate A) y = -Cos2x B) y = Sin2tetta - 2Cos2tetta C) f(tetta) = negative pie*Sin(2tetta - pie) Tetta means that zero with a line going horizontally across mid zero. Like In trigonometric identities you have ___ tetta....

thank you reiny

find the coordinates of all points on the graph of f(x) = x + 2cos(x) in the interval [0, pie] at which the tangent line is horizontal.

thank you Reiny

differentiate the function a) y = cos³x b) y = Sin²xCos3x c) y = Sin (x³)

a total of 8 meters of fencing are going to be used to fence in a rectangular cage for pets and divide it into three smaller cages **the photo that is shown with this question is three (3) boxes stuck together side by side horizontally*** determine the overall dimensions that ...

a total of 8 meters of fencing are going to be used to fence in a rectangular cage for pets and divide it into three smaller cages **the photo that is shown with this question is three (3) boxes stuck together side by side horizontally*** determine the overall dimensions that ...

Thank you Reiny! The first question (1st one) your calculations for the 2nd x is wrong. x = x = π + .5236 = 3.665192654 and not 2.61799

solve for (<_ = less than or equal to / pie = pie sign / -pie = negative pie) 3 sin²x = cos²x ; 0 <_ x < 2pie cos²x - sin²x = sinx ; -pie < x <_ pie

Hey Reiny, I think b) is wrong. I got: b)y' = 2SinxCos3x + CosxCos3x * (-Sinx) y' = 2SinxCos3x - SinxCosxCos3x ... and I am not sure how to do c)

differentiate the function ( a) y = cos³x b) y = Sin²xCos3x c) y = Sin (x³)

a) determine the derivative of y = sin2x b) determine the derivative of y = 2SinxCosx c) shoe that derivatives in parts a) and b) are equal d) explain why derivatives in parts a) and be should be equal.

find the coordinates of all points on the graph of f(x) = x + 2cos(x) in the interval [0, pie] at which the tangent line is horizontal.

Thanks Reiny, I have checked it over and it seems about right to me. Thank you.

Determine the equation of the tangent line to the function (² = square): f(x) = x + cos²x at x = pie/4

Thank you Steve

Determine the derivative of the function (² = square): a) y = (x² + x - 1)Sin²x b) y = (x² + 1)/Sin²x

physics
What is the momentum of a two-particle sys- tem composed of a 1300 kg car moving east at 100 m/s and a second 1300 kg car mov- ing west at 35 m/s? Let east be the positive direction. Answer in units of kg · m/s

physics
What is the momentum of a two-particle sys- tem composed of a 1300 kg car moving east at 100 m/s and a second 1300 kg car mov- ing west at 35 m/s? Let east be the positive direction. Answer in units of kg · m/s

chemistry
Why does specific heat increase the greatest when it's near its freezing point?

Determine the critical numbers and find the absolute maximum and minimum values of the function y = 8x^3 + x^4 for x e [-8,2]

Use the second derivative test to find the local minimum and maximum values of each function, wherever possible. A) f(x) = 16/x + x^2 B) s(t) = t^4 - 8t^3

The cost, in dollars, for the production of x felt-tipped pens is C(x) = 48 000 + 0.28x + 0.00001x^2, and the revenue is R(x) = 0.68x - 0.00001x^2. What production level maximizes profit?

geometry
What's the next number 360, 180, 60, 15...?

geometry
What's the next number 360, 180, 60, 15...?

statistics
Suppose that, for students who are enrolled in college algebra, 73 percent are freshmen, 48 percent are female, and 31 percent are female and are freshmen. Your answers below should be entered as decimals and rounded to three decimal places. Two students will be independently ...

Chemistry
Hi Dr. Bob, I am quite stumped on how to figure out when chemical equations have a REACTION or NO REACTION. I have read the material in my textbook and even took out a chemistry books for the "Utterly Confused" to try to figure this out. Example: Zn(s) + H3PO4(aq)--&...

Cemistry
Dr. Bob, you are correct I made a typo the reactants are NH4OH (aq) + H2CO3 (aq). My answer is still the same as above. Is my answer correct? I have not balanced it yet. Also,I believe there is no reaction, due to being weak electrolytes.

Cemistry
Hi, I've been trying to solve this chemical equation for the last 30 minutes and am only confusing myself. I am wondering if the product I obtained is correct. The question is to write a balanced equation for the below reaction and be sure to indicate the states and if ...

Chemistry help
I am confused as to how to solve the below problem. I am not sure which formula to use. At first I thought I calculate the molar mass of NaOH, followed by calculating moles of NaOH. But I don't have the mass of NaOH to calculate moles. Do I convert 10mL to grams to Be able...

Math
A city of 2,950,000 people has a 2.5% annual decrease in population. Determine the city's population after 4 years.

Chemistry
What is another way to test for hydrogen and oxygen; other than the burning splint test? My teacher gave us the hint of- Universal Indicator

trig.
A ladder 20 feet long leans against the side of a house. Find the height from the top of the ladder to the ground if the angle if the angle of elevation of the ladder is 80°

trig.
A ladder 20 feet long leans against the side of a house. Find the height from the top of the ladder to the ground if the angle if the angle of elevation of the ladder is 80°

Physics
question 3.. you are correct question 4 you are not correct

science
No. There would be no different seasons and there would be the same seasons all year

math
find the domain the function f(x)is square root x plus 3

physics
The coefficient of static friction between a block and a horizontal floor is 0.35, while the coefficient of kinetic friction is 0.12. The mass of the block is 4.5 kg. A horizontal force is applied to the block and slowly increased. (a) What is the value of the applied ...

Math
V = 1/3Bh 3(V)=Bh (multiply both side by 3 to cancel fraction) 3V/h=Bh/h (divide both by h to get rid of h) 3V/h=B B=3V/h

THANK YOU :)

A 5.0-kg block is at rest on a horizontal floor. If you push horizontally on the 5.0-kg block with a force of 10.0 N, it just starts to move. (a) What is the coefficient of static friction? (b) A 12.0-kg block is stacked on top of the 5.0-kg block. What is the magnitude F of ...

physics
A 5.0-kg block is at rest on a horizontal floor. If you push horizontally on the 5.0-kg block with a force of 10.0 N, it just starts to move. (a) What is the coefficient of static friction? (b) A 12.0-kg block is stacked on top of the 5.0-kg block. What is the magnitude F of ...

Algebra
during the first part of a canoe trip the canoe travels 71 miles at a certain speed. The canoe travels 7 miles on the second part of the trip at a speed 5mph slower. The total time of the trip is 3 hours. what are the speed in each part of the trip?

social work
If you were appointed Patient Advocate for a close relative (parent, sibling, spouse, child, etc.) would you be able to carry out their wishes, including a wish to end their life if...? Would age or disability make a difference in your ability to serve as their patient advocate?

statistics
state the null and alternative hypothesis for the following: You are investigating a complaint that "special delivery mail takes to much time to be delivered

Physics
How far to the nearest tenth of a meter can a runner running at 9 m/s run in the time it takes a rock to fall from rest 73 meters?

Physics
A speeder traveling at 40 m/s passes a motorcycle policeman at rest at the side of the road. The policeman accelerates at 1.92 m/s2. To the nearest tenth of a second how long does it take the policeman to catch the speeder?

Physics
A passenger in a helicopter traveling upwards at 17 m/s accidentally drops a package out the window. If it takes 9 seconds to reach the ground, how high to the nearest meter was the helicopter when the package was dropped?To the nearest meter what was the maximum height of the...

Physics
A car traveling at 14 m/s accelerates at 2.11 m/s2 for 14 seconds. To the nearest meter how far does it travel? To the nearest tenth of a m/s, what is the final velocity of the car in the previous problem?

Physics
A car traveling at 14 m/s accelerates at 2.11 m/s2 for 14 seconds. To the nearest meter how far does it travel?

Physics
A car accelerates at a constant rate from zero to 25.6 m/s in 10 seconds and then slows to 14.4 m/s in 5 seconds. What is its average acceleration to the nearest tenth of a m/s2 during the 15 seconds? What was the acceleration during the first 10 seconds?

Physics
A car accelerates at a constant rate from zero to 25.6 m/s in 10 seconds and then slows to 14.4 m/s in 5 seconds. What is its average acceleration to the nearest tenth of a m/s2 during the 15 seconds?

physics
A runner dashes from the starting line (x = 0) to a point 91 m away and then turns around and runs to a point 30 m away from the starting point in 25 seconds. To the nearest tenth of a m/s what is the average speed?

english
unscramle this word-crimeamsg

Cultue
I have a question from one of my problems I have to solve. When there is not much awareness about race, misconceptions are created to help people to identify with this group. How can these misconceptions further alienation/segregation?

History
When there is not much awareness about race, misconceptions are created to help people to identify with this group. How can these misconceptions further alienation/segregation?

Finance
Help me understand how lower wage earner's taxes can be cut when they do not pay taxes at the end of the year to begin with and most will receive more back from filing taxes than they pay in. Where is the greatest benefit?

Physics
R = 6378000 meters a₁ = R + (212 miles + 246 miles)/2 a₁ = 6746540 meters a₂ = R + 60 miles a₂ = 6474561 meters GMₑ = 3.986e14 m³ sec⁻² Energy per unit mass in present orbit. E₁/m = −GMₑ/(2a₁) E₁/m...

american history
3)king Ferdinand the second and queen Isabella 4)he's describing how theblabd is different from his and as hes seeing its different, he sees potential and how useful it could be for the queen. 5) "trees are different from those of our country as day is from night"...

english, can you check over my answers? thanks!
The coach pointed to the relief-pitcher. Th infinitive phrase is to the relief-pitcher It's a noun phrase?

Math 109
If an account has a 3.4% interest rate compounded monthly, how much money do you need to invest now to have \$10,460 in 10 years?

Math 109
Your cousin has just won the lottery and wants to create an account that will have \$100,000 in 16 years to help pay for their child's college tuition. If the account has a fixed interest rate of 4.6% compounded 3 times each year, how much money should they put into the ...

math
Wouldn't you do all the multiplication first, such as 4*2, and then divide that into 8 to =1; then 24-1+12=35? Where is my thinking faulty?

math
could you please solve and show steps for: 24-8/4*2+4(3)

math
could you please solve and show steps for: 24-8/4*2+4(3)

Its not meant to represent a line. :/ Create a shape for X and for Y that will make this true. Draw and label the shapes, then illustrate how the quotient was obtained. Your drawing must be neat and accurate

Given 1/3 Y÷1/2 X=4 Discuss its meaning. Create a shape for X and for Y that will make this true. Draw and label the shapes, then illustrate how the quotient was obtained. Your drawing must be neat and accurate.

algebra
ooh okay yeah that was so easy now that I look at it thank you so much..it was 10

algebra
ok I have a algebra question how do you find the missing number for 42-9=43-? how do I get the answer and I need to understand it? I think the answer might be 45

physics
please help: 2 horizontal forces, one 180.0 N and the other 200.0 N, are exerted in opposite directions on a boat on a lake. What is the net horizontal force on the boat? Thanks for your help.

physics
tow horizontal forces, one 180.0 N and the other 200.0 N, are exerted in opposite directions on a boat on a lake. What is the net horizontal force on the boat? Thanks for your help.

English
Which element of a short story would be most important to a story about a mad scientist stealing a secret weapon?

Calculus AB/AP
A tank with a rectangular base and rectangular sides is to be open at the top. It is to be constructed so that its width is 4 meters and its volume is 36 cubic meters. If building the tank costs \$8 per square meter for the base and \$4 per square meter for the sides, what is ...

Can it even be solved?

Lalph Rauren was famous for discovering potential models as he walked the streets of New York. One day he spotted four girls who later became top models: Amy, Mary, Kay, and Beth. One was discovered walking through an apartment building, one in a coffee shop, one in a shopping...

statistics
If there are 200 students in a sample, and the mean = 45 and the standard deviation = 4. How many of these students will have a score under 41?

Math
Lalph Rauren was famous for discovering potential models as he walked the streets of New York. One day he spotted four girls who later became top models: Amy, Mary, Kay, and Beth. One was discovered walking through an apartment building, one in a coffee shop, one in a shopping...

algebraic expressions
24/2*3-9*3

geometry
Thank you so much. I got confused when it said equilateral and it gave me two different units.

geometry
An equilateral triangle has sides that measure 5x+3 units and 7x-5 units. What is the perimeter of the triangle?

computer
On most Windows systems, where is the file location data stored? (Points: 5) a. Boot sectors b. DAT c. FAT d. Folders is it D

computer
Which of the following types of computers is considered a portable computer? (Points: 5) a. workstation b. mimicomputer c. server d. notebook is it D

computers
Which of the following types of memory contain data that cannot be modified by the user? (Points: 5) a. simm b. dimm c. RAM d. ROM is it D

math
kjlkj

Statistics
There is a formula which is n=(za/2)squared •^p•^q/E squared. when ^p and ^q is unknown, use both 0.5. za/2= 99% which is 2.575 ( Its at the chart A-2 at the bottom right). The margin of error is 0.03 which you also squared it. Looks like this: 2.575^2•0.5•...

real estate law
A tenancy at ______ may be terminated at any time by either party. a. leisure b. option c. necessity d. will is it A

chem 105
A gas mixture with a total pressure of 745mmHg contains each of the following gases at the indicated partial pressures: CO2, 257 mmHg; Ar, 123mmHg; and O2, 160 mmHg. The mixture also contains helium gas. What is the partial pressure of the helium gas? What mass of helium gas ...

Chem 105
A 1.5-L container of liquid nitrogen is kept in a closet measuring 1.3 m by 1.3 m by 1.8 m. Assuming that the container is completely full, that the temperature is 22.3 C, and that the atmospheric pressure is 1.2 atm , calculate the percent (by volume) of air that would be ...

chemistry 105
A 260-mL flask contains pure helium at a pressure of 743 torr. A second flask with a volume of 480 mL contains pure argon at a pressure of 715 torr. If the two flasks are connected through a stopcock and the stopcock is opened, what is the partial pressure of helium? in torr ...

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