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#501 Re: Help Me ! » Bearing problem. » 2013-07-21 21:54:10
There are several examples in the book, which there is no distance and bearing of locations provided,
But the book has the answer by using trigonometry to solve, but the book says it could be solved by vector approch as well. I will post another example of such problem.
#502 Re: Help Me ! » Bearing problem. » 2013-07-21 21:43:57
There several examples in the book, which distances and bearings was not provided, one example is what above.
#503 Re: Help Me ! » Bearing problem. » 2013-07-21 21:36:08
This how I solved it:
vector AB = (8km, 030 digrees).
Vector BC = (10km, 000).
I use 000 digrees, as the bearing from B to C, because it not provided.
Vector AB = (8cos60) = 8 * 0.5 = 4.
(8sin60) = 8 * 0.8660 = 6.928
Vector BC = (10 cos000) = 10 * 1 = 10.
(10sin000) = 10*0= 0.
To find distance, Vector AC = AB + BC.
AC = 4 + 10 = 14.
6.928 + 0 = 6.928.
By Pythag.
AC^2 = 14^2 + 6.928^2
=243.99. taking root
=15.620.
Bearing from North I had, 153.671.
Please, help me.
#504 Re: Help Me ! » Bearing problem. » 2013-07-21 20:56:35
I had:
(a) 320km.
(b) 263 digrees.
I think I am right. I used vector approach to solve.
I tried using vector approach to solve the following, but got it wrong, please help.
A cyclist starts from a point A travel 8 km in the distance 030 digrees to B and then 10 km to C. Find the cyclist's distance and bearing from A.
#505 Re: Help Me ! » Simplify the following: » 2013-07-21 04:03:38
I had: x^2-1/x^3 -2x^2 +x.
I dont understand how you got -x^2 +1. As the numerator.
Please, let me know how you got it.
Thanks
#506 Re: Help Me ! » Simplify the following: » 2013-07-21 03:19:04
Okay I would try and do thanks.
#507 Re: Help Me ! » Simplify the following: » 2013-07-21 02:59:13
Please I want to follow the procedure before getting the answer, the book gave me exactly your answer, but the workings was not shown.
Thanks once more.
#508 Re: Help Me ! » Simplify the following: » 2013-07-21 02:06:34
Errr okay, I see!
But Sirs please solve for me.
Thanks in advance.
#509 Help Me ! » Bearing problem. » 2013-07-21 01:15:00
- EbenezerSon
- Replies: 22
An aeroplane flew from town A, travels 200km at a bearing of 135 digree to town B. Then travels 250km from town B at a bearing of 045 digree to town C. Find using the vector approach
(a) the distance of A from C.
(b) the bearing of A from C.
Please solve this problem for me.
Thanks in advance.
#510 Re: Help Me ! » Simplify the following: » 2013-07-18 05:24:49
This is how the top right bracket looks: (x^1/2 - x^-1/2) The last X raises to the power negative one over two(x^-1/2).
Thanks.
#511 Re: Help Me ! » Simplify the following: » 2013-07-17 10:42:03
Simplify the following:
Please help me solve this. (x^3/2 + x^1/2) (x^1/2 - x^-1/2)/(x^3/2 - x^1/2)^2. I got x^2 - x + x/x^3 - x^2 - x^2 as the final answer. The book has x + 1/x(x - 1) as its answer which I don't comprehend. The book did not show the procedures.
Thanks in advance.
#512 Re: Help Me ! » Simplify the following: » 2013-07-15 09:57:33
= grouping like terms > 4m^2 - m^2 + 6mk +6mk - 2mk - 2mk + 9k^2 + 4k^2 This is where the mistake is.
-(m^2 - 2mk -2mk + 4k^2) = -m^2 + 2mk + 2mk - 4k^2[/b]
This is -1 times the bracket, so every term changes sign.
Thank you very much indeed Sir!
Errrr! That was where the mistakes stem from, candidly speaking I had thought, I one has to take off the bracket, after multiplication has taken place within the bracket.
I have now grown wary to multiply any sign outside the bracket after multiplcation has taken place within the bracket, especially negative signs.
Thanks Sir for the provision of the link, God bless.
#513 Re: Help Me ! » Simplify the following: » 2013-07-12 08:18:12
(2m^2 + 3k)^2 - (m - 2k)^2 . Please see how I solved it, and correct where I have made the mistakes so that I could identify it. Please.
Here I go:
(2m + 3k)^2 - (m - 2k)^2 = (2m + 3k)(2m + 3k) - (m - 2k)(m - 2k) . by expansion.
= Multiplying the first expansion > (2m + 3k)(2m + 3k) = 4m^2 + 6mk + 6mk + 9k^2.
Multiplying the second expansion > (m - 2k)(m - 2k) = m^2 - 2mk - 2mk + 4k^2.
= (4m^2 + 6mk + 6mk + 9k^2) - (m^2 - 2mk - 2mk + 4k^2)
= grouping like terms > 4m^2 - m^2 + 6mk +6mk - 2mk - 2mk + 9k^2 + 4k^2
= adding them > 3mk^2 + 12mk - 4mk + 13k^2
= 3mk^2 + 8mk + 13k^2.
Please this is how I got my answer, I know I am wrong but I cant help.
#514 Re: Help Me ! » Simplify the following: » 2013-07-12 07:53:16
I have understood #38 very well, but please, see how I came by that final answer, I have tried to understand how you solved it at #19 but still I haven't grasp it.
#515 Re: Help Me ! » Simplify the following: » 2013-07-11 07:12:33
I got:
3m^2 - 8km + 13k^2, Which is impossible for me to split the middle term.
Please help.
#516 Re: Help Me ! » Simplify the following: » 2013-07-11 07:08:23
Errr sir, that's good, so always to check, should I pick the numbers randomly in my head to do the substitution? To see if will get (0) as result for both? Or the figure I will get should be the same in each case? And not necessarily (0)?
#517 Re: Help Me ! » Simplify the following: » 2013-07-11 04:34:21
hi Ebenezerson
I think you'll need to multiply these brackets out like this
Then you can start to simplify.
Can you fill in the dots ?
Alternative way to do this:
difference of two squares:
Have you met this before ?
If so, you could put p = 2m + 2k and q = m - 2k
Bob
Sir this one, I tried resolving it my self with my understanding, but got different result, please I would be much obliged if you would take the pain to explain it to my understanding once more by manipulating each step. Please.
#518 Re: Help Me ! » Simplify the following: » 2013-07-11 00:03:28
The book gave this as the final answer:
(2a - 3b - c)(2a - 3b '- C')
I don't understand how it got the '-C', I think it should be '+C' instead.
What do you say?
#519 Re: Help Me ! » Simplify the following: » 2013-07-10 23:59:12
4a^2 - 12ab - c^2 + 9b^2
= 4a^2 - 12ab - 9b^2 - c^2
= 4a^2 - 6ab - 6ab + 9b^2
= 2a(2a - 3b) -3b(2a - 3b)
= (2a - 3b)(2a - 3b) = (2a - 3b)^2.
------------------------------------------
-----------------------------------------
(2a - 3b)^2 - c^2 = (2a - 3b - c)(2a - 3b + c). Is the final answer correct?
#520 Re: Help Me ! » Simplify the following: » 2013-07-10 09:07:53
At first, I did not spot that this is the difference of two squares. But then I noticed that (q^2 - 6qr + 9r^2) is a perfect square:
So try this:
put P = 3p and Q = (q - 3r) and use
Bob
Last but not the least could you help me with an illustration, how you got the (q - 3r)^2 ?. :-)
#521 Re: Help Me ! » Simplify the following: » 2013-07-10 08:50:26
Okay sir! but could you explain with an illustration, how you got the (q - 3r)^2 ?
In #19.
Thanks in advance.
#522 Re: Help Me ! » Simplify the following: » 2013-07-10 08:42:52
Please an assistance, please and why it should appear.
#523 Re: Help Me ! » Simplify the following: » 2013-07-10 08:38:46
Candidly speaking sir, I cant tell or explain why that negative sign should appear there, to be frank!
Whenever I am dealing with such complicated difference of two squares, positive and negative signs eludes me just in the end.
#524 Re: Help Me ! » Simplify the following: » 2013-07-10 08:27:21
= (3p)^2 - (q- 3r)^2
= (3p - q - 3r)(3p +q - 3r).
Is that correct?
#525 Re: Help Me ! » Simplify the following: » 2013-07-10 08:10:53
But please help me solve the third and the fourth ones.