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# c4 vectors

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Why bother with a post grad? Are they even worth it? Have your say! 26-10-2016
1. For part (e) working out the area of the triangle, why is my method of splitting the triangle into 2 and using Area =0.5absinC incorrect here? The answer should be 23.06

Is my diagram not accurate? my answers for a-d were correct.

thanks

Zacken
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2. your method gives the correct area if the diagram is correct.

it looks like there is a right angle in the corner ?
3. (Original post by the bear)
your method gives the correct area if the diagram is correct.

it looks like there is a right angle in the corner ?
I don't think it's a right angle, just looks like it from my rough sketch :P

https://a086a5a2f39bda93734c56a63fab...%20Edexcel.pdf

in the model answers by arsey I have the same diagram but just used a different method, so not sure why I'm wrong
4. (Original post by Katiee224)
I don't think it's a right angle, just looks like it from my rough sketch :P

https://a086a5a2f39bda93734c56a63fab...%20Edexcel.pdf

in the model answers by arsey I have the same diagram but just used a different method, so not sure why I'm wrong
is this yours or Arse's ? : https://a086a5a2f39bda93734c56a63fab...%20Edexcel.pdf

when i typed in your working i got 23.... maybe you were in radions or missed out a bracket ?
5. (Original post by the bear)
is this yours or Arse's ? : https://a086a5a2f39bda93734c56a63fab...%20Edexcel.pdf

when i typed in your working i got 23.... maybe you were in radions or missed out a bracket ?
They're the answers written by a member of this forum I believe,not mine
6. (Original post by Katiee224)
They're the answers written by a member of this forum I believe,not mine
anyway you were right... you must have typed it in wrong.
7. (Original post by the bear)
is this yours or Arse's ? : https://a086a5a2f39bda93734c56a63fab...%20Edexcel.pdf

when i typed in your working i got 23.... maybe you were in radions or missed out a bracket ?
hmm maybe you're right, I'll try them again in my calculator :P
8. (Original post by the bear)
anyway you were right... you must have typed it in wrong.
I get the right ans when I type both angles as 77.2, but when I type in my working out I posted above, I get 23.06?
9. (Original post by Katiee224)
I get the right ans when I type both angles as 77.2, but when I type in my working out I posted above, I get 23.06?
so what is the correct answer ?

10. (Original post by the bear)
so what is the correct answer ?

did you get 23.4 when typing in my answer?
11. (Original post by Katiee224)
did you get 23.4 when typing in my answer?
23.06158337
12. (Original post by the bear)
23.06158337
aw right so my answers wrong, I think both angles arr 77.2 degrees but I'm not sure why
13. (Original post by Katiee224)
aw right so my answers wrong, I think both angles arr 77.2 degrees but I'm not sure why
it may be because both angles have been rounded before the working out ?
14. (Original post by the bear)
it may be because both angles have been rounded before the working out ?
nope that's not it, both angles should be 77.2 according to the mark scheme but I'm not sure why

Zacken any ideas?
15. (Original post by Katiee224)
nope that's not it, both angles should be 77.2 according to the mark scheme but I'm not sure why

Zacken any ideas?
Where did you get 108.8 degrees from? It's a straight line, so both angles should add up to 180, yours ads up to 186. So the angle that's labelled 108.8 should be labelled 102.8.
16. (Original post by Zacken)
Where did you get 108.8 degrees from? It's a straight line, so both angles should add up to 180, yours ads up to 186. So the angle that's labelled 108.8 should be labelled 102.8.
my working looked like 108.8 from earlier, oops, I am making so many silly mistakes with c3 and c4

well atleast I know where I went wrong now

thanks for helping though both of you
17. (Original post by Katiee224)
my working looked like 108.8 from earlier, oops, I am making so many silly mistakes with c3 and c4

well atleast I know where I went wrong now

thanks for helping though both of you
No problem.

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