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# C2 TRIG HELP! Will +rep! watch

1. I need help with the question labeled 'e' and '3'

I dont even know were to start

2. (Original post by User32432432)
I need help with the question labeled 'e' and '3'

I dont even know were to start

For e. I would suggest multiplying by 2 to get rid of the fraction.

for 3. Use the trig identitiy and rearranging gives:
Now sub that in and you should be okay
3. (Original post by User32432432)
I need help with the question labeled 'e' and '3'

I dont even know were to start

You know that so from there:

you now have:

rearrange to get:

You can see this is in the form of a quadratic if you let

factorise to get (use quadratic formula or complete the square for this)

because you let , now

(HINT: is less than -1 so it is not a valid solution as must be between -1 and 1)

for e, I would first let , then solve for y in

when you have the solutions for y, get solutions of , and times all answers by 2 to get

Hope I helped!
4. for e. use the formula for cos(2x) and let x = theta / 2
for 3. use the identity sin^2(x) + cos^2(x) = 1 , rearrange and you can get a quadratic of cos(theta)
5. (Original post by Anythingoo1)
You know that so from there:

you now have:

rearrange to get:

You can see this is in the form of a quadratic if you let

factorise to get (use quadratic formula or complete the square for this)

because you let , now

(HINT: is less than -1 so it is not a valid solution as must be between -1 and 1)

for e, I would first let , then solve for y in

when you have the solutions for y, get solutions of , and times all answers by 2 to get [latex]theta[\latex]

Hope I helped!
Wow! Yes you did help Thanks sooo much <3
To + rep do I just like your posts ? if so comment and I'll like more and if you could look at this

http://www.thestudentroom.co.uk/show....php?t=2297725
6. (Original post by User32432432)
Wow! Yes you did help Thanks sooo much <3
To + rep do I just like your posts ? if so comment and I'll like more and if you could look at this

http://www.thestudentroom.co.uk/show....php?t=2297725
Yeah but there's a limit to how many you can +rep per day I think, it's no problem at all it's helpful for me because I'm trying to familiarise myself with latex, and with rep I'm not doing this for rep I just like helping people, but I won't say no if you're offering

If you have any more questions I'm happy to help.
7. (Original post by Anythingoo1)
Yeah but there's a limit to how many you can +rep per day I think, it's no problem at all it's helpful for me because I'm trying to familiarise myself with latex, and with rep I'm not doing this for rep I just like helping people, but I won't say no if you're offering

If you have any more questions I'm happy to help.
for part e can you confirm my answers ?

I got 135,-135,225,-225

Thanks

EDIT: for part 3 I have Sin^2=4Cos(-2+5^1/2)

What do I do from there ?
8. (Original post by User32432432)
for part e can you confirm my answers ?

I got 135,-135,225,-225

Thanks

EDIT: for part 3 I have Sin^2=4Cos(-2+5^1/2)

What do I do from there ?
Yes solutions are fine for part e, just remember that

Erm, not really sure what you've done there, see my above working guide...
9. (Original post by Anythingoo1)
Yes solutions are fine for part e, just remember that

Erm, not really sure what you've done there, see my above working guide...
I checked what I did..... I though you just sub in the value of CosX into the equation ?

So I got Sin^2X=4Cos(-2+5^1/2)

But I'm not sure what to do from there ?

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