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# C3 - Can somebody please explain this identity? Watch

1. Now the bit I'm confused with is how to get from step 2 to 3. I know you divide by on both denominator and numerator.

My question is how does this work? I'm on about in the case of In this sense you are in effect dividing by zero??

I know this isn't the case and I'm being stupid, but I just want to know why :P Thanks
2. You wouldn't need to worry about that because whenever cos x = 0 then tan x is undefined: Wolfram
3. (Original post by Goldfishy)
You wouldn't need to worry about that because whenever cos x = 0 then tan x is undefined: Wolfram
Ahhh that makes sense

How about in this identity then:

(divide by )

How does that work when ??
Ahhh that makes sense

How about in this identity then:

(divide by )

How does that work when ??
Observe that which you have used in your calculations. So when is undefined

EDIT: Cheers for the rep, returned.
5. (Original post by Goldfishy)
Observe that which you have used in your calculations. So when is undefined

EDIT: Cheers for the rep, returned.

Oh aha Thank you so much for clearing that up for me

And thank you for the rep!
Oh aha Thank you so much for clearing that up for me

And thank you for the rep!
No problem
Ahhh that makes sense

How about in this identity then:

(divide by )

How does that work when ??
You're not actually carrying out the division, you're literally just rewriting it or changing the form.

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