Math Is Fun Forum

Peaches47

Member

Registered: 2008-02-17

Posts: 13

Find all solutions(Trig)

I need to get the tricks of the trade on this one.

Find all solutions of the equation:

cot x sec x= 2 cot x

Note:  I am trying to teach my self this math all my classes are taken on line, my instructor pretty much just refers me to  websites for more information, so what ever detailed info that anyone can give me I am sure it will help me understand how to figure these type of questions out.
Thanks

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Struggling Middle Aged Math Student

JaneFairfax

Member

Registered: 2007-02-23

Posts: 6,868

Re: Find all solutions(Trig)

Simplify the equation. You should find that it comes down to

which you can solve easily.

vidyasagar2007

Member

Registered: 2008-02-21

Posts: 1

Re: Find all solutions(Trig)

cot x sec x= 2 cot x

secx = 2 cotx / cotx

secx = 2

Cosx = 1/2

Therefore, x = 60 degrees (if x is acute)

JaneFairfax

Member

Registered: 2007-02-23

Posts: 6,868

Re: Find all solutions(Trig)

is just ONE solution, not all solutions. The question is asking for ALL solutions. Try again.

By the way, to be absolutely careful, the first part should be done thus:

However

which would leave sec(x) = 1⁄cos(x) undefined. Hence cot(x) ≠ 0. This is just a precaution to make sure we don’t overlook any potential solutions.

Last edited by JaneFairfax (2008-02-21 04:55:14)

Peaches47

Member

Registered: 2008-02-17

Posts: 13

Re: Find all solutions(Trig)

Thank You both the information was helpful

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Struggling Middle Aged Math Student