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## #1 2017-07-23 21:02:08

tyuighp
Member
Registered: 2015-12-04
Posts: 12

### Find all angles θ

Find all angles θ in [0, 2π) for which
sin θ + cos θ + tan θ + cot θ + sec θ + csc θ = 6.4

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## #2 2017-07-25 19:03:25

NakulG
Member
Registered: 2014-09-02
Posts: 186

### Re: Find all angles θ

Sin2θ = -1, 0.96, 26

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## #3 2017-07-25 19:07:28

bob bundy
Registered: 2010-06-20
Posts: 8,508

### Re: Find all angles θ

hi NakulG

I hadn't got anywhere with this.  Please would you give a few hints/.  Thanks

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 Bundy

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## #4 2017-07-25 19:53:03

NakulG
Member
Registered: 2014-09-02
Posts: 186

### Re: Find all angles θ

sinθ + cos θ = x and sinθcosθ=y
substituting we get
x^3 - 6.4x^2+x+8.4=0
Solve for x, so x = -1, 1.4 & 6

Hope this helps...

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## #5 2017-07-25 20:06:47

bob bundy
Registered: 2010-06-20
Posts: 8,508

### Re: Find all angles θ

hi NakulG

Many thanks for that.  I'll give it a try.

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 Bundy

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## #6 2017-07-25 22:18:14

NakulG
Member
Registered: 2014-09-02
Posts: 186

:-)

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## #7 2017-07-25 23:02:57

bob bundy
Registered: 2010-06-20
Posts: 8,508

### Re: Find all angles θ

hi NakulG

Yep!  Got it now.  That's an inspired substitution!  Thanks once again.  colon bracket with no minus gives a on this forum.

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 Bundy

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## #8 2017-08-01 08:15:26

NakulG
Member
Registered: 2014-09-02
Posts: 186

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