#1

Alright, I've started doing some preliminarily work for A2. This also means Mechanics.

It's not so bad so far, I'm just iffy on a few things so far on my work on vectors and thought to bring it here.

8. The vector a is in the plane Oxy, where Ox, Oy are the coordinate axis, and makes an angle 30 degrees with Ox, as in the above diagram (I'm too lazy to draw it out). Find the components of a long Ox and Oy when a equals;

There's four parts of this question if someone could do one of them (when a equals 6) I could try doing the rest from there.

Even easier one but for some reason I cannot get the direction at all. I keep getting the same answer which is wrong.

In a regatta a yacht sails x km due east from a marker O then y km due north to a buoy B. Calculate the magnitude and direction of the displacement vector OB> when

b. x=5, y=8

It's not so bad so far, I'm just iffy on a few things so far on my work on vectors and thought to bring it here.

8. The vector a is in the plane Oxy, where Ox, Oy are the coordinate axis, and makes an angle 30 degrees with Ox, as in the above diagram (I'm too lazy to draw it out). Find the components of a long Ox and Oy when a equals;

There's four parts of this question if someone could do one of them (when a equals 6) I could try doing the rest from there.

Even easier one but for some reason I cannot get the direction at all. I keep getting the same answer which is wrong.

In a regatta a yacht sails x km due east from a marker O then y km due north to a buoy B. Calculate the magnitude and direction of the displacement vector OB> when

b. x=5, y=8

#2

Lies! It IS another maths thread

Edit: Don't forget about bearings, that north is 0 degrees, and not 90. That used to mess me up all the time.

Edit: Don't forget about bearings, that north is 0 degrees, and not 90. That used to mess me up all the time.

#3

Both questions are just Pythagoras dressed up with stupid wording.

#4

Lies! It IS another maths thread

Edit: Don't forget about bearings, that north is 0 degrees, and not 90. That used to mess me up all the time.

That might help some other stuff I was iffy on actually, cheers.

0 to 360 in a clockwise then?

#5

a(Ox) = 6cos30, a(Oy) = 6sin30 I think but I haven't done this sort of stuff in a while.8. The vector a is in the plane Oxy, where Ox, Oy are the coordinate axis, and makes an angle 30 degrees with Ox, as in the above diagram (I'm too lazy to draw it out). Find the components of a long Ox and Oy when a equals 6

#6

Both questions are just Pythagoras dressed up with stupid wording.

Question eight has only two figures so I can't use Pythagoras just yet.

The other one I'm after the angle. The pythag part of that is easy, I just keep getting the wrong angle.

#7

The angle from the x axis is sin^(-1) [sqrt(5^2+8^2) / 8] and the magnitude is sqrt(5^2+8^2)In a regatta a yacht sails x km due east from a marker O then y km due north to a buoy B. Calculate the magnitude and direction of the displacement vector OB> when

b. x=5, y=8

again, I could be wrong, my maths is a bit rusty

#8

That might help some other stuff I was iffy on actually, cheers.

0 to 360 in a clockwise then?

Yeah.

#9

In question 8 use simple sin and cos. It's basically a right-angled triangle where the hypotenuse is 6cm long. Then get the base and height and put them into vector form.

#10

a(Ox) = 6cos30, a(Oy) = 6sin30 I think but I haven't done this sort of stuff in a while.

Damn, that's all it is?

And yeah, that's actually correct. Cheers for that.

I'm working from a poor book with no actual help so there may be a few of these threads popping up.

#11

Damn, that's all it is?

And yeah, that's actually correct. Cheers for that.

I'm working from a poor book with no actual help so there may be a few of these threads popping up.

Well keep it one thread then will ya?

#12

The angle from the x axis is sin^(-1) [sqrt(5^2+8^2) / 8] and the magnitude is sqrt(5^2+8^2)

again, I could be wrong, my maths is a bit rusty

After re-wording I'm getting a lot of Math errors on the calculator. Mind re-writing that?

#13

Well keep it one thread then will ya?

Might make the next one an official help Craigo do Mechanics thread

#14

Forget the first bit - I was doing it a stupid way. It's just inverse tan (8/5)

#15

Eh that was quite easy.

#16

Forget the first bit - I was doing it a stupid way. It's just inverse tan (8/5)

Already tried. It's wrong.

Wait, crap! After doing that in about four different ways, getting the same answer, turns out I was reading the wrong answer. I had it correct the first million times...

#17

Already tried. It's wrong.

Wait, crap! After doing that in about four different ways, getting the same answer, turns out I was reading the wrong answer. I had it correct the first million times...

*waits for the Help Craigo do Basic English Thread*

#18

*waits for the Help Craigo do Basic English Thread*

Dyslexic

#19

typical...

The textbooks we had when I was taking M1 were all new first editions and full of errors - loads of the answers were wrong.

The textbooks we had when I was taking M1 were all new first editions and full of errors - loads of the answers were wrong.

#20

Dyslexic

Excuses

typical...

The textbooks we had when I was taking M1 were all new first editions and full of errors - loads of the answers were wrong.

The textbooks we have are third edition and still have loads of incorrect answers.

The books were written by mathematicians, but I can't see how they could let them go into print (for the third time mind you) with so many maths-related fu

*ckups.*

#21

Well I think usually the questions are written by the book writer's students. Certainly students do the proof-reading (at a ****ty rate of pay)The textbooks we have are third edition and still have loads of incorrect answers.

The books were written by mathematicians, but I can't see how they could let them go into print (for the third time mind you) with so many maths-related fuckups.

I want to write a maths textbook myself some day - I'm planning on doing a masters in maths education once I finish my current degree.

#22

Excuses

The textbooks we have are third edition and still have loads of incorrect answers.

The books were written by mathematicians, but I can't see how they could let them go into print (for the third time mind you) with so many maths-related fuckups.

Yeah, the publisher I'm using is quite reknowned for it and it's bloody annoying.

And I was tempted to add in to my post 'inb4Dyslexia'snotanexcuseforstupidity'

I don't care, I joke about it and how miraculous it was I got an A in English Language at GCSE

#23

........I feel about as useful as a condom machine in the Vatican in this thread

#24

Well I think usually the questions are written by the book writer's students. Certainly students do the proof-reading (at a ****ty rate of pay)

I want to write a maths textbook myself some day - I'm planning on doing a masters in maths education once I finish my current degree.

Awesome.

What's your educational history anyway? You always appear to be an patronising sod around the forums on academic matters

#25

I've got A-levels in maths, further maths, physics, chemistry and religious studies. I'm doing my degree in physics with photonics and nanotech. I took most of last year out for health reasons so I'm re-doing my second year this year.Awesome.

What's your educational history anyway? You always appear to be an patronising sod around the forums on academic matters

I don't mean to patronise but I can't help being very opinionated

#26

Boyce puts on a clever facade, but I see through it.

#27

I'm not sure whether to or

#28

I've got A-levels in maths, further maths, physics, chemistry and religious studies. I'm doing my degree in physics with photonics and nanotech. I took most of last year out for health reasons so I'm re-doing my second year this year.

I don't mean to patronise but I can't help being very opinionated

Psst. Arrogance and being egotistical are virtues, regardless of wingey opinions anyone else may give.

#29

Yeah exactly. If you don't have confidence in your opinions, you're probably wrong.