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# Trigonometry urgent help please :)

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1. Hi guys,
Please could someone kindly help me with the question in the attachment. The first part was to prove the first part in red and I managed to do that. But I'm stuck on finding the values of X.

Any help will be appreciated.
Attached Images

2. (Original post by Aty100)
Hi guys,
Please could someone kindly help me with the question in the attachment. The first part was to prove the first part in red and I managed to do that. But I'm stuck on finding the values of X.

Any help will be appreciated.
What have you tried so far for the second part?
3. (Original post by SeanFM)
What have you tried so far for the second part?
This is what I thought about doing but I'm not sure.

Also that should say square root 😂
Attached Images

4. (Original post by Aty100)
This is what I thought about doing but I'm not sure.

Also that should say square root 😂

You know from here yeah?
5. (Original post by The-Spartan)

You know from here yeah?
there is another possibility ....when you do the square root ?
6. (Original post by Aty100)
This is what I thought about doing but I'm not sure.

Also that should say square root 😂
A substitution like y = tanx may help you, so you have y^2 = 1. Then you could say that y^2 - 1 = 0 and then use something to help you progress.
7. (Original post by the bear)
there is another possibility ....when you do the square root ?
Haha just noticed that as you replied, silly me XD
8. (Original post by The-Spartan)

You know from here yeah?
Omg I totally forgot 😂 Thank You!

1/4 pi
5/4 pi
3/4 pi
7/4 pi
9. (Original post by Aty100)
Omg I totally forgot 😂 Thank You!

1/4 pi
5/4 pi
3/4 pi
7/4 pi
Right on
SeanFM stated another useful method that you could use,
and so
Difference of two squares was what the trick here was,

And so you get
.
10. (Original post by The-Spartan)

√1 = 1
±√1 = ±1
11. (Original post by 04MR17)
√1 = 1
±√1 = ±1
Erm... No.

To show, lets take the inverse:
,
.

12. (Original post by The-Spartan)
Erm... No.

To show, lets take the inverse:
,
.
Irrelevant. If you are going to put + Ans. Then you have to have a + before the √.
13. (Original post by 04MR17)
Irrelevant. If you are going to put + Ans. Then you have to have a + before the √.
Oh, thought you were saying that the square root does not equal plus or minus
Hmm, ive always written it as
14. (Original post by The-Spartan)
Oh, thought you were saying that the square root does not equal plus or minus
Hmm, ive always written it as
This thread should clear things up
15. (Original post by SeanFM)
This thread should clear things up
Oh gawd, i've omitted the plus/minus on all of my square roots my whole life and only put them in the answer
Think i need a break from maths for a couple days
16. (Original post by The-Spartan)
Oh gawd, i've omitted the plus/minus on all of my square roots my whole life and only put them in the answer
Think i need a break from maths for a couple days
It's okay at A-level you can kind of get away with not knowing, apart from integration by substitution where you need to know.

Urgh, latex is being a nightmare.

If you had a substitution with u = x^(1/2) and the limits of x are 0 and 9, then the limits of u are 0 and 3 rather than 0 and -3.
17. (Original post by SeanFM)
It's okay at A-level you can kind of get away with not knowing, apart from integration by substitution where you need to know.

Urgh, latex is being a nightmare.

If you had a substitution with u = x^(1/2) and the limits of x are 0 and 9, then the limits of u are 0 and 3 rather than 0 and -3.
Yeah no i get the whole roots thing, my notation was just off instead of writing
where i needed the i would just write . If i didn't need the negative root id omit the entirely, which is wrong really
Another one of my notation errors, along with the implies arrows (i use nearly all the time, when i can't xD)
18. (Original post by The-Spartan)
Oh, thought you were saying that the square root does not equal plus or minus
Hmm, ive always written it as
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