GCSE Edexcel Maths Unit 3 19/06/2012 Exam Discussion

I don't like sohcahcoa, can I not just use the sine and cosine rule instead?


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Thank god, just that it was in the spec, how likely is loci to come up its in the spec but I've never heard of
It!!


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OK its a loooong time since I done that, but basically its the distance from an object, in no given direction e.g saying an area around an school in which buses will be served to.
If you are given two or more loci you can use this information to find possible places where something could be e.g someone is 5 km away from the airport and 3 km away from the police station and the station and airport are 7 km away from each other....
what you could do is draw a spot for each building 7cm away from each other ( 1cm=1km as a scale and then draw using a compass circles around each building one with radius 3cm (the station) and the other radius of 5cm ( the airport), where the circles overlap is the possible places the person could be

Loci is used satellite navigation, by using this with 3 satellites to determine a exact location.

Does this help ?

sohcahtoa is a lot easier if every time you write it out like this
o a o
s h c h t a

Then you have three formula triangles

OK that didnt work :L stupid TSR formatting it

So would opposite be sine of angle times by hypotenuse ?


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yes... let me write it out a way tsr my understand ><

o
s h
a
c h
o
t a

Cover up what you want to find out and x or / what you have
e.g in the triangle cover up the top, times the bottom two together, if one of the bottom corners of the triangle is covered up divide the top by what you left uncovered at the bottom

Oh this came up on my mock exam only got 1 out of 3 marks for it but I think I know what I'm doing now. Thankyou very much!!


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Ohhh Thankyou! Amazing what tips you get on here. If you dont mind me asking when do you use sine-1 ect?


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be careful whether they want to find out the area where e.g the person could be as if i said within 5km of the airport and within 3km of the station, what you probably do is shade the area the circles overlap. but if its exact distances away like i originally said, then you should in the case i used get two exact answers

e.g sinx=1/2
sinx = 0.33
to find x
or x could be theta ( the angle)
same goes for cos-1 and tan-1

Thanks so finding the angle is sin-1 ect. Thankyou.


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I think it's positive 3x because you're subtracting the 5x from the left hand side from the 8x on the right hand side, and 8x - 5x = 3x :P

Sorry for the late reply, you can edit it if you click the yellow bar at the top which says "enable editing". You have really good grades and are in a good position . You need 130 out of 160 so roughly 65 out of 80 for an a*. Good luck

How many marks out of 80 would you guys predict A*/A/B?
afterall it's new spec so it could be extremely high or extremely low

For bounds, my teacher said that:

6.43 to 2 decimal places would be:

Highest value = 6.434???? Isn't it 6.435?

HELP