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## #1 2007-02-22 02:05:58

ganesh
Moderator
Registered: 2005-06-28
Posts: 21,730

### Trignometry Ex.1

1. If

,
what is tan A?

2. If

,
find the value of
.

3. If

,
find the value of

4. If 3 tanθ = 4, determine the value of

.

5. If 5cosθ-12sinθ=0, what is the value of

?

6. If 16cotA=12, find the value of

.

7. Prove that

.

8. Prove that

.

9. Prove that

.

10. Prove that

.

It is no good to try to stop knowledge from going forward. Ignorance is never better than knowledge - Enrico Fermi.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

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## #2 2007-03-30 22:11:52

serhat38
Member
Registered: 2007-03-30
Posts: 6

### Re: Trignometry Ex.1

if sinA=5/13 so cosA=12/13 then sinA/cosA=tanA (5/13)/(12/13)=5/12=tanA

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## #3 2007-03-30 22:47:31

serhat38
Member
Registered: 2007-03-30
Posts: 6

### Re: Trignometry Ex.1

the value of second question is 1

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## #4 2007-03-30 22:49:12

serhat38
Member
Registered: 2007-03-30
Posts: 6

### Re: Trignometry Ex.1

value of third question is -9/7

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## #5 2007-03-30 22:50:17

serhat38
Member
Registered: 2007-03-30
Posts: 6

### Re: Trignometry Ex.1

the value of forth question is 1/7

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## #6 2007-03-30 22:51:28

serhat38
Member
Registered: 2007-03-30
Posts: 6

### Re: Trignometry Ex.1

the value of fifth question is 17/19

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## #7 2007-03-30 22:53:07

serhat38
Member
Registered: 2007-03-30
Posts: 6

### Re: Trignometry Ex.1

the value of sixth question is 1/7

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## #8 2007-03-30 22:56:59

serhat38
Member
Registered: 2007-03-30
Posts: 6

### Re: Trignometry Ex.1

(sin+cos)\(sin-cos)=[(sin\cos)+1]\[(sin\cos)-1]

=[(sin+cos)\cos]\[(sin-cos)\cos]
=(sin+cos)\(sin-cos)

so (sin+cos)\(sin-cos)=(sin+cos)\(sin-cos)

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## #9 2007-03-30 23:03:50

serhat38
Member
Registered: 2007-03-30
Posts: 6

### Re: Trignometry Ex.1

if tan.cot=1

(1-tan)\(1+tan)=(cot-1)\(cot+1)

cot+1-tan.cot-tan=cot-1+tan.cot-tan

so 1-tan.cot=tan.cot-1

2=2tan.cot
tan.cot=1

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## #10 2007-03-30 23:06:14

serhat38
Member
Registered: 2007-03-30
Posts: 6

### Re: Trignometry Ex.1

tan.tan=(sin.sin)\(cos.cos)

tan.tan.cos=(sin.sin)\(cos.cos)\cos
=(sin.sin)\cos
=(sin\cos).sin
=tan.sin

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## #11 2007-03-30 23:11:13

serhat38
Member
Registered: 2007-03-30
Posts: 6

### Re: Trignometry Ex.1

now dear ganesh please solve this

cos2∏\11+cos4∏\11+cos6∏\11+cos8∏\11+cos10∏\11=?

the value is a rational

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