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# Maths c2 help watch

1. Tanx=cosx

-pi <x <pi
2. (Original post by ramshahk)
Tanx=cosx

-pi <x <pi
Whats the identity for tanx?
Should be able to form a quadratic from that.
3. (Original post by an_atheist)
Whats the identity for tanx?
Should be able to form a quadratic from that.
-pi <x <pi
How would you form a quadratic
4. (Original post by ramshahk)
-pi <x <pi
How would you form a quadratic
tanx=sinx/cosx
in the question tanx=cosx, so sinx/cosx=cosx. If we bring the cosx up, we get sinx=(cosx)^2. What other identity can you use?
5. (Original post by an_atheist)
tanx=sinx/cosx
in the question tanx=cosx, so sinx/cosx=cosx. If we bring the cosx up, we get sinx=(cosx)^2. What other identity can you use?
The question says -pi <x<pi
6. (Original post by ramshahk)
The question says -pi <x<pi
That's a limit on the range of values x can take. In theory there are an infinite number of points where tanx=cosx.
For the minute, ignore it.
7. (Original post by an_atheist)
That's a limit on the range of values x can take. In theory there are an infinite number of points where tanx=cosx.
For the minute, ignore it.
Okaay
8. Tanx = Cosx

Sinx / Cosx = Cosx

Sinx = Cos^2x

Sinx = 1 - Sin^2x

Sin^2x + Sinx - 1 = 0

Let y = sinx

y^2 + y - 1 = 0

i think this is how u do it but i probably made a mistake somewhere

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9. (Original post by DamnDaniel2)
Tanx = Cosx

Sinx / Cosx = Cosx

Sinx = Cos^2x

Sinx = 1 - Sin^2x

Sin^2x + Sinx - 1 = 0

Let y = sinx

y^2 + y - 1 = 0

i think this is how u do it but i probably made a mistake somewhere

Posted from TSR Mobile
Looks good. Just trying to avoid giving this guy the answer on a plate, since it will help him more in the long run.
10. (Original post by an_atheist)
Looks good. Just trying to avoid giving this guy the answer on a plate, since it will help him more in the long run.
Yh I realised after! So sorry

Should've given the first 2 steps or just the identity they should've used and then left it there

Posted from TSR Mobile

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Updated: February 8, 2017
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