[Pika-Profiterole]

Good afternoon.

I would like some help for some questions on trigonometry in Core 3 Maths.

There is one question that I tried many times but I did not get it right:

Show that cosec x + cot x = 1/ cosec x - cot x (cosec x does not equal to cot x).

In my calculation (as below):

cosec x + cot x = 1/ cosec x - cot x

1/ Sin x + 1/ Tan x

1/ sin x + cos x/ sin x

1 + cos x / sin x

(1 + cos x / sin x)^2

1 + cos^2 x / sin^2 x

1 + (1-sin^2 x)/ sin^2 x

2 - sin^2 x/ sin^2 x

(2/sin^2 x) - 1

2 (1/sin^2 x) -1

2 cosec^2 x - 1 (That's the final answer I have calculated)

So have I made a massive mistake or over complicated anything in my calculation? (I always over-complicate things in my calculation >.<`)

Please do tell show me on which stage did I done it wrong! Hopefully I will not make the same mistake in exams never ever again!

Many thanks,

[TenOfThem]

Are you trying to show that



RHS






Can you finish this off

[Pika-Profiterole]

(Original post by TenOfThem)
Are you trying to show that



RHS






Can you finish this off

@o@
May I ask, how did you get ?

would you mind to explain step by step? (Sorry!! I really don't understand it >.<)

[TenOfThem]

I turned the fraction over

And then I multiplied numerator and denomination by (1+cos)

[Lord of the Flies]

(Original post by Pika-Profiterole)
...

You have overcomplicated the question a tiny bit.

Why not just show that

(it can be done in two lines)

For future reference, Maths questions belong here

[Pika-Profiterole]

Yes, I done it but in a different way.

I multiply both side by (cosec x - cot x)-- and my final answer is:
1 - cos^2x = sin^2

It just so different to the method that my teacher taught us... but the good news is I understand it, finally!! Haha..

Thank you so much for helping me.

By the way, I am doing maths questions (again!) amd there are two questions that I am not really sure is my calculation correct!

Would you like to check it for me please?

[Lord of the Flies]

(Original post by Pika-Profiterole)
Yes, I done it but in a different way.

I multiply both side by (cosec x - cot x)-- and my final answer is:
1 - cos^2x = sin^2

It just so different to the method that my teacher taught us... but the good news is I understand it, finally!! Haha..

Thank you so much for helping me.

By the way, I am doing maths questions (again!) amd there are two questions that I am not really sure is my calculation correct!

Would you like to check it for me please?

No problem, PM your working to me.