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## #1 2012-12-01 00:19:33

unlucky guy
Guest

### proving identities

my teacher is evil and won't explain everything. he wants brides and stuff like that... he gave only one easy example about trigonometric function and gave 48 exercises as a homework including problems.

please can u help me with this one...

prove that sin t + sec t = tan t is not an identity.                and please with little bit more explanation about how you solving

## #2 2012-12-01 00:42:43

bobbym
bumpkin
From: Bumpkinland
Registered: 2009-04-12
Posts: 109,606

### Re: proving identities

Hi unlucky guy;

One of the easiest ways is to find an obvious counterexample:

so sec(0)  is 1 / 1 because cos(0) is 1.

because

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

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unlucky guy
Guest

thanks

## #4 2012-12-01 01:06:34

bobbym
bumpkin
From: Bumpkinland
Registered: 2009-04-12
Posts: 109,606

### Re: proving identities

Hi;

Please let me know what your evil teacher thinks of it. He sounds like a moderator I know on another forum. If they are the same, he will absolutely hate my answer...

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

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## #5 2012-12-01 03:11:51

unlucky guy
Guest

### Re: proving identities

no he isn't im sure

## #6 2012-12-01 08:17:35

bobbym
bumpkin
From: Bumpkinland
Registered: 2009-04-12
Posts: 109,606

### Re: proving identities

Hi;

Okay, good luck then and welcome to the forum.

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

Offline