### Author Topic: Urgent Vector Problems (like, need ASAP if possible)  (Read 1874 times)

0 Members and 1 Guest are viewing this topic.

#### trust

• Guest
##### Urgent Vector Problems (like, need ASAP if possible)
« on: June 07, 2006, 09:44:24 PM »
I need these tomorrow morning (test) so if anyone is on break now and can get these done I'd be forever indebted.

1. Find two solutions for the triangle with angle A=61, side b = 18, side a = 17.

Note from me: There are two solutions, the one I got was angle B = 68, angle C = 51, and side c = 15

2. Let AB be a vector with initial point (-4, -1) and terminal point (-2, -5)

- Write vector in component form
- Write vector as a linera combination
- Find Magnitude

3. Find the angle between/ state the relationship of the vectors
a) v=i+2j       w=2i-j
b) v=3i-7j       w=-2i+14/3j
c) v=<5.4, -2.3> w=<13.5, -6.9>

4. Find a unit vector in the direction of v=3i-2j

5. Given vector a = <-5, 12>
a) Find the vector parallel to vector a but with a magnitude of 39
b) Find the vector opposite of vector a but with a magnitude of 26
c)  Find the vector orthogonal to vector a but with magnitude of 52

• Hero Member
• Posts: 2165
##### Re: Urgent Vector Problems (like, need ASAP if possible)
« Reply #1 on: June 07, 2006, 10:17:26 PM »
algebra 2?
i just took my final yesterday so im brain dead right now

#### Newby

• x86
• Hero Member
• Posts: 10878
• Thrash!
##### Re: Urgent Vector Problems (like, need ASAP if possible)
« Reply #2 on: June 07, 2006, 10:19:18 PM »
I know how to do them, but I don't care enough to do them.

I did like, half of those on my math final today, though.
- Newby
http://www.x86labs.org

Quote
[17:32:45] * xar sets mode: -oooooooooo algorithm ban chris cipher newby stdio TehUser tnarongi|away vursed warz
[17:32:54] * xar sets mode: +o newby
[17:32:58] <xar> new rule
[17:33:02] <xar> me and newby rule all

I'd bet that you're currently bloated like a water ballon on a hot summer's day.

That analogy doesn't even make sense.  Why would a water balloon be especially bloated on a hot summer's day? For your sake, I hope there wasn't too much logic testing on your LSAT.

#### dark_drake

• Mufasa was 10x the lion Simba was.
• x86
• Hero Member
• Posts: 2447
• Dun dun dun
##### Re: Urgent Vector Problems (like, need ASAP if possible)
« Reply #3 on: June 07, 2006, 11:01:10 PM »
1) The other triangle, using the ambiguous case, is A=61, a=17, B=112, b=18, C=7, c =2.

I assume you wanted everything rounded to the nearest whole, but just in case...

A=61, a=17, B=112.17005612591556, b=18, C=6.829943874084435, c=2.3115065868979543

Edit: We know that A=61, a=17, and b = 18.  a/sinA=b/sinB.  All I did was used the supplement of the first value of B I found (68) in place of the original.  Sin 68 = Sin 112.  I just went from there.
« Last Edit: June 08, 2006, 12:45:23 AM by dark_drake »
errr... something like that...

#### dark_drake

• Mufasa was 10x the lion Simba was.
• x86
• Hero Member
• Posts: 2447
• Dun dun dun
##### Re: Urgent Vector Problems (like, need ASAP if possible)
« Reply #4 on: June 07, 2006, 11:08:58 PM »
2)a) (2, -4)
b) 2i-4j
c)sqrt(20)

Edit: a) If I did this correctly, all I had to do was find out how far it moved. ((-2)-(-4),(-5)-(-1))
b)Once I had part a, I just changed it to linear form or whatever it's called.
c) Pythagorean theorem.
« Last Edit: June 08, 2006, 12:49:33 AM by dark_drake »
errr... something like that...

#### dark_drake

• Mufasa was 10x the lion Simba was.
• x86
• Hero Member
• Posts: 2447
• Dun dun dun
##### Re: Urgent Vector Problems (like, need ASAP if possible)
« Reply #5 on: June 07, 2006, 11:28:02 PM »
3)a)90  The vectors have the same magnitude, but are at right angles to each other.
b)0  The 2nd vector is 2/3s the first and is opposite.
c)176  I didn't really see a relationship.  Taking a shot in the dark, but is w supposed to be w=16.2, -6.9?

Edit: I can't really explain these.  I drew rough sketches of them and filled in the angles and side lengths.

If you need me to draw the pictures to show, I will.
« Last Edit: June 08, 2006, 12:58:53 AM by dark_drake »
errr... something like that...

#### dark_drake

• Mufasa was 10x the lion Simba was.
• x86
• Hero Member
• Posts: 2447
• Dun dun dun
##### Re: Urgent Vector Problems (like, need ASAP if possible)
« Reply #6 on: June 07, 2006, 11:50:38 PM »
4)(3/sqrt(13), -2/sqrt(13))

Because the magnitude is sqrt(13), we have to divide everything by sqrt(13) to get the vector to be a unit vector.
errr... something like that...

#### dark_drake

• Mufasa was 10x the lion Simba was.
• x86
• Hero Member
• Posts: 2447
• Dun dun dun
##### Re: Urgent Vector Problems (like, need ASAP if possible)
« Reply #7 on: June 08, 2006, 12:04:41 AM »
5)a)(-15, 36)
b)(10,-24)
c)Not sure if there's supposed to be 2, but here goes: (48, 20) and (-48, -20)

And yes, I did all of this to raise my post count.

Edit: Magnitude = 13
Parallel means same direction, but it had to be 3x larger, so I multiplied by 3.
Opposite means, well, opposite direction, so I changed the signs.  It had to be 2x the magnitude, so I multiplied by 2.
Orthogonal means at a right angle to, or perpidicular to.  So, I found the slope of the first vector was -5/12.  Therefore, the slope of the vector I was looking for was 12/5.  However, it had to be 4x larger, so I multiplied by 4.  I put the second one on there, (-48, -20), because it is opposite to the first one I found.
« Last Edit: June 08, 2006, 01:05:46 AM by dark_drake »
errr... something like that...

#### trust

• Guest
##### Re: Urgent Vector Problems (like, need ASAP if possible)
« Reply #8 on: June 08, 2006, 12:05:58 AM »
algebra 2?
i just took my final yesterday so im brain dead right now

analysis.

Thanks dark_drake, you're awesome. Do you have your work saved? If not, no big. If you do could you scan/copy and paste/whatever it?
« Last Edit: June 08, 2006, 12:09:51 AM by OG Trust »

#### dark_drake

• Mufasa was 10x the lion Simba was.
• x86
• Hero Member
• Posts: 2447
• Dun dun dun
##### Re: Urgent Vector Problems (like, need ASAP if possible)
« Reply #9 on: June 08, 2006, 12:41:49 AM »
algebra 2?
i just took my final yesterday so im brain dead right now

analysis.

Thanks dark_drake, you're awesome. Do you have your work saved? If not, no big. If you do could you scan/copy and paste/whatever it?
I didn't really write much down, and on top of that, I don't have a scanner, but I'll try to say how I found it in each one.

Edit: There you go.  Not sure if my explanations helped, but I tried.
« Last Edit: June 08, 2006, 01:06:47 AM by dark_drake »
errr... something like that...