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1. ### Difference Quotient - average rate of change

Thank you Mentallic, greatly appreciated.
2. ### Difference Quotient - average rate of change

This is still confusing me.. The equation represents the difference quotient f(2+h)− f(2) /h it represents the slope of the secant line through the points (2, f (2)) and (2+h, f(2+h)) on the curve. But i used this equation to find the DQ = -h+1 in the first place - feels like I am going...
3. ### Difference Quotient - average rate of change

Thank you Ray, I am a mature age student trying to nut things out for myself, I don't always have access to teachers, tutors etc - so its a challenge most of the time. I appreciate the response. Regards
4. ### Difference Quotient - average rate of change

Ray I appreciate your comments. However your reply is bordering on "well aren't you an idiot" I have used this forum for a few years now, and never once have I received a reply like this. Not everyone fully understands calculus as you do - Just a simple " did you realize that you have...
5. ### Difference Quotient - average rate of change

Hi TT, that's where I am stuck, I am not sure as to the next step. Can I assume that the answer to the previous question is correct?
6. ### Difference Quotient - average rate of change

Homework Statement Original function f(x) = -x^2+5x-2 I have calculated the difference quotient as -2x-h+5 Then use difference quotient to calculate the average rate of change: for the following x=2 and x=2+h I need this to go on to the next part of the question and i wanted to ensure...
7. ### Graphing functions and identifying features

Many thanks, I appreciate the guidance.
8. ### Graphing functions and identifying features

Thank you, yes, you are right. I think just a lack of confidence in this aspect of Maths. Sorry to be a bother. Regards

10. ### Graphing functions and identifying features

Homework Statement Hi there I need assistance with two graphs that are causing me some problems y=e(^-2x)(-1) and y=ln(x-2)+1 Homework Equations I just need some guidence as to where to start - starting with a table - what range is approriate? The Attempt at a Solution Stuck
11. ### Evaluating logarithms given log(a)b = 3

Hi there Can someone please review my work and advise. Homework Statement Given log(a)b=3 , use the properties of logs to evaluate 4log(a)(1/b)+2log(a)b^3 Homework Equations I used the rules log(a)1 = 0 log(a)(x/y) = log(a)x-log(a)y log(a)x^m = mlog(a)x The...
12. ### Projectile motion - help needed

Projectile motion - urgent help needed Homework Statement Target is projected at an an angle to the horizontal, initial speed 4 m/s, unknown angle and unknown distance to the target. Height of the target is 0.8m. Need to find the minimum angle. Homework Equations v= u+at v =...
13. ### Photoelectric effect

I agree, it does making asking about the kinetic energy redundant - I think it is a typo.. Many thanks for all your help on this one.
14. ### Photoelectric effect

The first question has the wavelength at 180 mm not nanometers. Convert that to meters is 0.18 m. Cheers
15. ### Photoelectric effect

Homework Statement Hi there. I have two questions and in both I believe that no photoelectrons will be emitted from the surface. Question 1 A metal with a work function of 9 x 10^-19 J is irradiated with UV radiation of wavelength 180 mm. Will photoelectrons be emitted from the...
16. ### Coordinate Geometry- distance between two points

Many thanks to all respondants, I appreciate all your help with this one. Cheers
17. ### Coordinate Geometry- distance between two points

Hi Homework Statement Two points X(a,b) and Y(b,a) Prove that the distance = sqrt2 (a-b) Homework Equations d = sqrt(x2-x1)^2 + (y2-y1)^2) The Attempt at a Solution I have drilled it down to (sqrt 2b^2+2a^2-4ba) but unable to drill it down to sqrt2 (a-b) Help...
18. ### Back EMF and induced current

Homework Statement Describe with the aid of diagrams how the back emf and induced current vary in a single-coil DC motor over one full rotation of the armature. Give particular attention to the rate of change of flux in the coil and to the direction(s) of the DC and induced current...

20. ### Maximum and Minimum voltage

Hi there, and help! I have been attempting to nut this out and could use some guidance. I think that I have the equation right now E(max) = 2 x n (turns) x B(in tesla)x L x v sin (theta). Based on the info already available (see previous post) the max voltage is 1000 V. Can someone please...
21. ### Maximum and Minimum voltage

I think I have worked it out, can someone please confirm. 10 Hertz converted to radians is 62.83, therefore my volts would drop to 314 V and minumum - if e = 0, then the minimum voltage should be 0. Cheers
22. ### Maximum and Minimum voltage

Homework Statement Hi there, motor and generator gurus Suppose a generator has the following specifications, and the rotor turns with frequency 10 Hz. Determine the maximum and minimum value of the voltage generated, using the formula: ε = Βlv n = 1000 loops = 1000 B = 10 Tesla I...
23. ### Area between curves

Ive adjusted the contrast and looks okay on my mac - let me know if it is still faint. Cheers
24. ### Area between curves

Homework Statement Using the domain 0 < x < pi sketch the two functions y=2sin(x/3) and y = 2x/pi on the same axes. Find the area Homework Equations The Attempt at a Solution I have sketch the graphs. And attached my working so far - can someone confirm my workings so far...
25. ### Transformer efficiency conversion

Hi all I am still a standstill on this question as I don't have a power factor included in the question. Assistance greatly appreciated. Cheers P
26. ### Logs and Exponential

Thanks Mark, for all your help. Cheers
27. ### Logs and Exponential

Thanks HOI, I am getting two different answers and getting confused. Ill have another look at this. Cheers
28. ### Logs and Exponential

Really sorry, If x = 12.4 Find the value of ... correct to two sig fgures 8^(4x/3) (divided by sign) log(base 10 subscript) (5x-3/x^0) - this is exactly how the question is written. x to the 0 power is 1 so log(base10)(5x-3/1) = log 59 8 to the power of 4x/3 if you substitute 12.4 into...
29. ### Logs and Exponential

Hi Mark For this question - I need to substitute 12.4 into all x values. (5x-3/x to the power 0) so if you substitute 12.4 into the x in this part of the equation (12.4^0), yes, you will get (5(12.4)/1). Is a substitution question. I don't yet understand how to add the Maths chararcters...
30. ### Logs and Exponential

Homework Statement Greetings - can someone please check my work, many thanks Homework Equations If x = 12.4 Find the value of ... correct to two sig fgures 8^(4x/3) / log(base 10) (5x-3/x^0) The Attempt at a Solution = 8^(16 8/15) / log(base 10) (5(12.4)-3 / 1) = 4.8 x 10^14 (via...
31. ### Transformer efficiency conversion

I have a further question about the efficiency calculation - to ensure that I get Watts for both input and output - can I convert VA to the following. A small transformer used to power a laptop computer has the following characteristics printed on it: • input AC 220 V, 50 Hz, 15 VA (Does...
32. ### Transformer efficiency conversion

Hi there Many thanks, can you advise on how to set the calculation out. Im confused about the 15VA part of the question can I use 15 VA in the equation or do I need to convert it to another unit type?? and also determining a value for the efficiency, how can that be done? Cheers P
33. ### Transformer efficiency conversion

Greetings physics gurus Im getting bogged down on conversion of the VA to A Homework Statement A small transformer used to power a laptop computer has the following characteristics printed on it: • input AC 220 V, 50 Hz, 15 VA. • output DC 5.0 V, 1.0 A. Is this transformer...
34. ### Primary voltage and transformers

Many thanks Cheers P
35. ### Primary voltage and transformers

Hi physics gurus Homework Statement What should the primary voltage be changed to in order to produce a secondary current of 10 A, given that the V / I ratios for the coils do not change? Current ratios that I have calculated so far are as follows: Np (200) Vp (1200) Is (15)...
36. ### Integration - areas

Sorry, oooopppsss, can I say 48.6pi u3? I got the impression that I had gone horribly wrong. Manythanks for you responses. Cheers P
37. ### Integration - areas

\pi\int_a^b\left(f(x)\right)^2dx y^2 = x and line y = 3 becomes y^4 = pi [y^5/5] 3 to 0 = pi [243/5] Example http://www.intmath.com/Applications-integration/4_Volume-solid-revolution.php Cheers P
38. ### Integration - areas

Thanks Mentallic Yes, I realize I know the volume formulae. I calculate the volume would be 48.6 units cube - do you mind checking? Cheers P
39. ### Integration - areas

Homework Statement Find the area enclosed by the y axis, the line y = 3 and the curve x = y^2 Homework Equations [/b]3. The Attempt at a Solution [/b] Area = \int 3 to 0 y^2.dy = (1/3 y^3) 3 to 0 = (1/3 x 27) = 9 sq units...
40. ### Rational Functions

Im finding the rational functions diffcult for some reason, sorry just not getting it at the moment. Many thanks, I will try and nut it myself. Cheers P
41. ### Rational Functions

Part b) I use the f '(x) to find the turning point and determine their nature. I think that the second derivative is - (2x/(x^2-1) or - (2x/(x-1)^2(x+1)2 Therefore the stationary points where dy/dx = 0 ie x = +1 and -1 Therefore when x = +1 y + 0 and when x = -1 y = 0...
42. ### Rational Functions

Hi there b) to f) is causing the problem Many thanks P
43. ### Rational Functions

Hi there I have a Rational function y = 1 / x^2-1 . I have a good idea what the graph looks it, it will have vertical asymptotes at -1 and 1 and I can work out the y intercept (-1 concave down). However I'm not sure about the other parts to the question. Homework Statement dy/dx...
44. ### Space travel - time dilation

Thanks AM - you have the patience of a saint - yes, I did mean "mind". Many thanks. P
45. ### Sling Shot question

Thank you Filip for your assistance. Now this makes sense. CHeers P
46. ### Space travel - time dilation

Hi there AM - many thanks for your patience - its not an easy subject to get my around. Should that be \gamma*0.1044? Cheers P
47. ### Space travel - time dilation

Hi AM Thank you both for your asistance - depending on the number of figures used - you could end up with 7.07 rounding or 7.38 years (7.38) which is the same as part b) (c) How much time has passed on Earth’s clock, as seen from the spacecraft ? How do you tell which is the most...
48. ### Space travel - time dilation

Hi resaypi - this has confused me, sorry.
49. ### Space travel - time dilation

Hi AM t2 = 70.7 * (522.05 - (0.9999)(522)/(3.00^8)2 still get a strange figure. t2 = 8.02^-17 again this looks strange. Sorry to be such a pain.
50. ### Sling Shot question

The question is as stated no additional information. Formula comes from 1. Applying the conservation of momentum to this collision KVi - vi = KVf + vf 2. Applying the conservation of kinetic energy KVi^2 + vi^2 = KVf^2 + vf^2 Solving equations simultaneously for vf leads to the...