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Pearson Edexcel C1/2 Question

Show that (cos^2x-sin^2x)/(1-sin^2x) = 1-Tan^2x
I have no idea its a 2 mark question so it should be simple.
I got to (1-2sin^2x)/(cos^2x) and dont know what to do next.
Reply 1
Avatar for Notnek
Notnek
21
Original post by Tom22561
Show that (cos^2x-sin^2x)/(1-sin^2x) = 1-Tan^2x
I have no idea its a 2 mark question so it should be simple.
I got to (1-2sin^2x)/(cos^2x) and dont know what to do next.

Denominator :

1−sin⁡2A≡cos⁡2A1-\sin^2 A \equiv \cos^2 A
Reply 2
Avatar for Tom22561
Tom22561
OP
14
Original post by notnek
Denominator :

1−sin⁡2A≡cos⁡2A1-\sin^2 A \equiv \cos^2 A


Already did that and got

1-2sin^2x divided by cos^2x and what to do next?
Reply 3
Avatar for Zacken
Zacken
22
Original post by Tom22561
Show that (cos^2x-sin^2x)/(1-sin^2x) = 1-Tan^2x
I have no idea its a 2 mark question so it should be simple.
I got to (1-2sin^2x)/(cos^2x) and dont know what to do next.


Leave the numerstor as it is:

(cos^2 x - sin^2 x) / cos^2 x = (cos^2 x)/cos ^2 x - (sin^2 x)/cos ^2 x = ...

Edit: too late, dammit phone!
Reply 4
Avatar for Tom22561
Tom22561
OP
14
Original post by Zacken
Leave the numerstor as it is:

(cos^2 x - sin^2 x) / cos^2 x = (cos^2 x)/cos ^2 x - (sin^2 x)/cos ^2 x = ...

Edit: too late, dammit phone!



Thank you soo much i knew it was something simple :smile:
Reply 5
Avatar for Notnek
Notnek
21
Original post by Zacken
Leave the numerstor as it is:

(cos^2 x - sin^2 x) / cos^2 x = (cos^2 x)/cos ^2 x - (sin^2 x)/cos ^2 x = ...

Edit: too late, dammit phone!

Your posts just don't look right without LaTeX :smile:

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