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#1 2014-08-07 04:18:55

niharika_kumar
Member
From: Numeraland
Registered: 2013-02-12
Posts: 1,062

trig. equation

solve the equation:-




It is simplified in


pls give me the hint to proceed.


friendship is tan 90°.

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#2 2014-08-07 19:53:56

Bob
Administrator
Registered: 2010-06-20
Posts: 10,053

Re: trig. equation

hi Niharika,

That's a tough one.  I haven't thought of an algebraic method for this.  Back in my youth, when algebra failed we were taught to draw an accurate graph and read off the answer that way.  Would that be acceptable here ?

You could substitute x = tan^2 theta, which would simplify the task:

That has two solutions, one negative (approx. -1.2) and one positive (between 3 and 4).

These would suggest that there isn't a simple solution like pi/6.

Bob


Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob smile

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#3 2014-08-07 23:53:35

Agnishom
Real Member
From: Riemann Sphere
Registered: 2011-01-29
Posts: 24,974
Website

Re: trig. equation

That has two solutions, one negative (approx. -1.2) and one positive (between 3 and 4).

How did you solve that one?


'And fun? If maths is fun, then getting a tooth extraction is fun. A viral infection is fun. Rabies shots are fun.'
'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'
I'm not crazy, my mother had me tested.

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#4 2014-08-08 00:16:38

Bob
Administrator
Registered: 2010-06-20
Posts: 10,053

Re: trig. equation

draw an accurate graph

See other post with link to function grapher.

Bob


Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob smile

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#5 2014-08-08 04:02:55

niharika_kumar
Member
From: Numeraland
Registered: 2013-02-12
Posts: 1,062

Re: trig. equation

how to construct the graph of 2^x.


Don't we have some other way other than graphs?


friendship is tan 90°.

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#6 2014-08-08 04:34:44

Agnishom
Real Member
From: Riemann Sphere
Registered: 2011-01-29
Posts: 24,974
Website

Re: trig. equation

Use geogebra or the function grapher in MIF


'And fun? If maths is fun, then getting a tooth extraction is fun. A viral infection is fun. Rabies shots are fun.'
'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'
I'm not crazy, my mother had me tested.

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#7 2014-08-08 21:23:20

niharika_kumar
Member
From: Numeraland
Registered: 2013-02-12
Posts: 1,062

Re: trig. equation

yes I used that function grapher.

I am not friendlier with geogebra.


friendship is tan 90°.

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#8 2014-08-09 04:25:07

Agnishom
Real Member
From: Riemann Sphere
Registered: 2011-01-29
Posts: 24,974
Website

Re: trig. equation

M wrote:

Methods available to Solve or NSolve are not capable of solving the following:

x^2-1==2^x

Last edited by Agnishom (2014-08-09 04:25:46)


'And fun? If maths is fun, then getting a tooth extraction is fun. A viral infection is fun. Rabies shots are fun.'
'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'
I'm not crazy, my mother had me tested.

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#9 2014-08-09 04:30:06

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

Re: trig. equation

Solve is for polynomials.

FindInstance[x^2 - 1 == 2^x, x, Integers, 2]

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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#10 2014-08-09 04:32:07

Agnishom
Real Member
From: Riemann Sphere
Registered: 2011-01-29
Posts: 24,974
Website

Re: trig. equation

I have done this.

You already know that this is not what I want.

Side Note: Please check the ACP if the default theme is Air because it does not look so when logged out


'And fun? If maths is fun, then getting a tooth extraction is fun. A viral infection is fun. Rabies shots are fun.'
'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'
I'm not crazy, my mother had me tested.

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#11 2014-08-09 04:33:59

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

Re: trig. equation

You already know that this is not what I want.

What do you want?

What is ACP?


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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