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1. Related rates

a women is walking at a rate of 6 ft/sec across a bridge 40 ft above the water, a man in a boat is immediately below the woman on the bridge , at right angles to the bridge and at the rate of 4 ft /sec. how fast is the man and woman seprating at the end of 10 seconds what i have figured out...
2. Chain rule

g(x) = (4+csc^2(3x))^1/2? it is this one it was orginally the squrt of 4+csc^2(3x) i just attempted to simplify it
3. Differentiation rule ?

f(t) = 400t+70/t+1 represents the temp. in an oven and f(t) is in F degrees first i used the quotient rule and got 330/(t+1)^2 = f'(t) A) the rate of change in temp of the ove with respect to the time of 2 minutes after turnig the oven on and at 10 minutes i pluged 2 and 10 in...
4. Chain rule

g(x) = (4+csc^2(3x))^2 this is what i got 1/2(4+csc^2(3x))^-1/2 * d/dx (4+csc^2(3x) g'(x) = 1/2(4+csc(3x))^-1/2 (1+cot3) did i go about this correct to get the answer or did i mess it up at the diretive part? joe
5. Struggling on this one

y = x*square root of 3 + 2sinx find the x coordinate on (0,2pie) of the points where y has a horizonal tangent line I am really lost and struggling on getting this started :cry: :confused: thanks joe
6. Calculus answer check

Am I goong about these two problems correctly? A) F(x) = (xsinx)(cosx) find F'(x) f(x)*d/dx(g(x) + g(x) * d/dx F(x) product rule F'(x) = xsinx d/dx (cosx) + cos x d/dx xsinx = xsinx*(-sinx) + cos x *(xcosx) = -xsin^2 x^2 + xcos^2 x^2 is that right B) F(x) = xe^x/ x^2 +...
7. How to approach this problem

If F(x) -64/x^2 and it wants me to find an equation that decribes its position at (8,-1) which way do you think is best to find this out using the division of deritives or get it by limts
8. Vertical asymptotes

The question is fine a equation f(x) that has a vertical asymptotes of X=1and X=3 and a horizontal asymptotes of Y=1 A) (x-1)(x-3) / y-1 = x^2-4x+3 / x-1 OR B) (x-1) /(x-1)(x-3) = just the oppsite of above is any of these correct? I think B is correct but right now I can't...
9. 5 years since my last math class

I don't know much about it , and reading the scetion is difficult to understand. I have been going to math lab and looking for a tutor to assist me with my struggles. but at least i am on the right track. You said that this function passes through 0. Do I need to pick a point greater than...
10. One more limit ?

Can anybody help me get started on this the radical in the Numerator gots me lost. F(x) = 3-sq root x / 9-x has a removable discontinuity at x=9. define a new function g(x) such that g=f everywhere except at x = 9 , but is continuous everywhere. :confused: thanks joe
11. 5 years since my last math class

It has been at least 5 years since my last math class and I am kinda struggling. The question is: Use the intermediate value theorem to show that there is a root of ln x = e^-x on the interval (1,2). Find the correct root to 3 decimal values What i have so far f(1) = ln 1...
12. Struggling in econ

:confused: Suppose a firm in a perfectly competive industry is producing a output of 10 units. The firms total revenue at this output is $80 and its total cost is$30. The firms marginal cost associated with the 11 unit of a output is \$12. What can i say about an increase in production should...
13. Concave mirror

thanks for that information because I was going to ask the question tuesday
14. Index of refraction

In this figure the path of the light passes from air to glass. Calculate the index of refraction n1 = air = 1 n2 = glass = ? Sin theta 1 = 30degrees sin theat 2 is = 20 degrees formula used n2 = n1*sin theta 1 / sin theta 2 sin of 30/ sin of 20 = n2 = 1.46 is this correct hope the...
15. Concave mirror

not sure really where the image is i didn't think you could have a negitive distance joe
16. Concave mirror

if a double concave mirror with a focal length f = -20 inches is used , where does the image seem to be located , if the image is 30 feet away from the lens first i converted the 30ft to inches and got 360inches used formula 1/p + 1/q = 1/f .0028 + 1/q = -.05 1/q = -.053 q = -18.9...
17. Mirror question

The rear view on the passenger side of late model cars warn us theat objects may be closer than they appear. I think the mirror used is convex. But why is that type of mirror selected? thanks joe
18. Light rays through a window pane

I know a prisim can be used to disperse white light into colors. This does not happen when a beam of light passes through a window pane.Why not?( the light may or may not be entering the glass window along the normal. The light does not disperse into colors). thanks
19. Answer check / little help

A proton traveling at 3E6 m/s enters a region where the electric field has a magnitude of 3E5 N/C. The electric field is uniform and slows the proton's motions. a)calculate the distamce the proton will travel before coming to a momentary halt? B)Calculate the decel. of the proton and the...
20. Going in right direction electric field

The question is a charge object has a mass of 9.11E-31 kg and a charge of 1.602E-19 coul. Calculate the strength of the electric field that would provide a force equal to the weight of the charged object E = Fe/m 1.602E-19 / 9.11E-31 E = 1.76E 11 joe
21. Zener circuit help

thanks i found a pretty good example in an old text i had thanks again joe
22. Zener circuit help

This is what i have so far the knowns Vs= 50v Vz = 10 v Iz = 32mA R1 = 1K ohm Rl =? "potentmeter" i just got the multisim program and could draw the cir if need be R1 is in series with the source and the zener and rl are in parallel it wants me to determine the range of Rl, Il...
23. Transistor ?

still struggling and REALLY don't know how to go about this problem thanks joe
24. Transistor ?

The emitter current in a certian npn transitor is 8 mA. If .8% of the minority carrier injected into the base recombing with the holes, find the base current , collector current and the exact value of alpha i am not sure how to get this started thanks joe
25. Determine the change in internal energy of boiling water

Thanks alot for the reply, at least i am starting to get a grasp on this subject. And doing better in the class Thanks again Tom joe
26. Determine the change in internal energy of boiling water

Determine the change in internal energy of 1 kg of water at 100 degrees C when it is fully boiled. Once boiled this volume of water changes to 1671 Liters of steam at 100 degrees C Assume the pressure remains constantat 1 atm things i know 1 L =1E-3 m3 1atm = 1.013E5 N/m2 1 L = 1000 cm3 =...
27. Internal energy

Now if my Q is right and I use drags and Doc Als conversion then U is equal to 2.09E6 J is that correct these were some of the hw questions i didn't finish Thanks alot Joe :smile:

Thanks J Man
29. Internal energy

Seem to have ran into a brick wall with this problem Determine the change in internal energy of 1 kg of water at 100 degrees C when it is fully boiled. Once boiled this volume of water changes to 1671 Liters of steam at 100 degrees C Assume the pressure remains constantat 1 atm things i know...
30. How much has the cable stretched?

A truck is pulling a car out of a ditchwith a steel cable that is 9.1 meters long and has a radius of .5cm. When the car just begins to move the tension of the cable is 890N. How much has the cable stretched? converted .5cm to .005m area of the wire A = pie*r^2 Y = 20E10 (steel) used the...