The Student Room Group
Uni students - Complete our survey >>
Uni students - Complete our survey >>
Uni students - Complete our survey >>

Trigonometric Identities Help!!

Scroll to see replies

Reply 60
Avatar for Alex.trin
Alex.trin
OP
10
Original post by RDKGames
Use the identity sin⁡2x+cos⁡2x≡1\sin^2{x}+\cos^2{x}\equiv 1 to get sin squared in terms of cos squared.

Right so this is what I've got:
1-cos^2/1-cosx = 1+cosx
Reply 61
Avatar for Alex.trin
Alex.trin
OP
10
Original post by ellahick
RDK games, he/she doesn't do maths - common sense here "ALEX"

I don't know what's more confusing: the maths or your weird replies
Original post by Alex.trin
Are you by any chance religious?


I must say i find my religious beliefs highly irrelevant to your maths problems however for the sake of it I will admit I'm a member of the church of england who also dabbles in Islam and all things Allah
Reply 63
Avatar for Notnek
Notnek
21
Original post by Alex.trin
Right so this is what I've got:
1-cos^2/1-cosx = 1+cosx

This one's a bit trickier than the questions that you've done so far.

You need to factorise the numerator by using difference of two squares. Can you do that?
Original post by Alex.trin
I don't know what's more confusing: the maths or your weird replies


I don't know whats more original, the idea of heaven and afterlife or your comments
Reply 65
Avatar for Alex.trin
Alex.trin
OP
10
Original post by notnek
This one's a bit trickier than the questions that you've done so far.

You need to factorise the numerator by using difference of two squares. Can you do that?

Oh yes I see it now. Is it (1-cosx)(1+cosx) on the top?
Reply 66
Avatar for Alex.trin
Alex.trin
OP
10
Original post by ellahick
I must say i find my religious beliefs highly irrelevant to your maths problems however for the sake of it I will admit I'm a member of the church of england who also dabbles in Islam and all things Allah

Unfortunately this thread doesn't regard religion so please can you make your religious beliefs useful somewhere else?
Original post by alex.trin
oh yes i see it now. Is it (1-cosx)(1+cosx) on the top?


is it not obvious you retarded child of satan
Original post by Alex.trin
Unfortunately this thread doesn't regard religion so please can you make your religious beliefs useful somewhere else?


Any chatrooms you would recommend?/
Reply 69
Avatar for Alex.trin
Alex.trin
OP
10
Original post by notnek
This one's a bit trickier than the questions that you've done so far.

You need to factorise the numerator by using difference of two squares. Can you do that?

Wow I did it. 2 questions lefts!!
Reply 70
Avatar for Alex.trin
Alex.trin
OP
10
Original post by ellahick
Any chatrooms you would recommend?/


Any of the threads on this page, take your pick:
http://www.thestudentroom.co.uk/forumdisplay.php?f=133
Reply 71
Avatar for Alex.trin
Alex.trin
OP
10
Original post by notnek
This one's a bit trickier than the questions that you've done so far.

You need to factorise the numerator by using difference of two squares. Can you do that?

Ok so I'm on question 7 now. I'm up to 1+sinx/cosx = cosx/1-sinx. I would love some help please !
Original post by Alex.trin
Ok so I'm on question 7 now. I'm up to 1+sinx/cosx = cosx/1-sinx. I would love some help please !


Try starting from the RHS and multiplying the top and bottom by 1+sinx
Reply 73
Avatar for Alex.trin
Alex.trin
OP
10
Original post by ValerieKR
Try starting from the RHS and multiplying the top and bottom by 1+sinx

Ok so on the RHS I've now got cosx+cosxsinx/1-sin^2x. Is this right and where do I go from now?
Has your teacher showed you how to set these out?

If you are starting with the left hand side then write LHS = ....... and work on that to eventually get what is on the RHS.

As others have said do not put them equal until you have shown they are.

I'm quite surprised your teacher is doing this so early in the year ... [I'm a teacher and would not start with this yet]
Original post by Alex.trin
Ok so I'm on question 7 now. I'm up to 1+sinx/cosx = cosx/1-sinx. I would love some help please !


Original post by ValerieKR
Try starting from the RHS and multiplying the top and bottom by 1+sinx


NNOOOOOOOOOOOOOOOOOO.!!!!!

Valerie, same pitfall I made. Look onto the first page.

Alex, go back a step, on the LHS, multiply top and bottom by cosx. Express denominator in terms of sinx, and use difference of two squares again. Factors cancel and you have it.
Reply 76
Avatar for Alex.trin
Alex.trin
OP
10
Original post by Muttley79
Has your teacher showed you how to set these out?

If you are starting with the left hand side then write LHS = ....... and work on that to eventually get what is on the RHS.

As others have said do not put them equal until you have shown they are.

I'm quite surprised your teacher is doing this so early in the year ... [I'm a teacher and would not start with this yet]

Well we all did further maths in June so we're just recapping some of the A* content which is likely to appear in the AS before we forget it completely.
Reply 77
Avatar for Alex.trin
Alex.trin
OP
10
Original post by RDKGames
NNOOOOOOOOOOOOOOOOOO.!!!!!

Valerie, same pitfall I made. Look onto the first page.

Alex, go back a step, on the LHS, multiply top and bottom by cosx. Express denominator in terms of sinx, and use difference of two squares again. Factors cancel and you have it.

I've gone wrong somewhere: cosx + cosxsinx/1-sin^2x = cosx/1-sin^2x
Original post by RDKGames

Valerie, same pitfall I made. Look onto the first page.


You can start from either side, so long as you end up at the other
Original post by Alex.trin
I've gone wrong somewhere: cosx + cosxsinx/1-sin^2x = cosx/1-sin^2x


You had 1+sin⁡xcos⁡x\frac{1+\sin{x}}{\cos{x}} and now refer back to my comment on what to do.

Quick Reply

Related discussions

Latest

Trending

Trending

Articles for you