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#1 2013-03-23 16:48:35
- Agnishom
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Trigonometric Equation
If in a triangle,
Then,
What is the value of sin angle A?
Is it 8/27?
'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'
'The whole person changes, why can't a habit?' -65
#2 2013-03-23 19:20:56
- bob bundy
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Re: Trigonometric Equation
hi Agnishom
How did you get that? It's not what I'm getting.
Here's my method.
SINE RULE is:
So I put
and re-arranged to get
Different values of k will make different sized circles but all the resulting triangles will be similar => same three angles.
So it is ok to take a = √6, b = 2√2, c = 3√3
Use the cosine rule to get cosA and hence sinA.
I made it
Bob
You cannot teach a man anything; you can only help him find it within himself..........Galileo Galilei
#3 2013-03-23 19:38:29
- Agnishom
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Re: Trigonometric Equation
bob bundy wrote:
hi Agnishom
SINE RULE is:
So I put
and re-arranged to get
I have the following doubts:
I. How did you do the rearrangement?
II. How do you know what to put for a?
'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'
'The whole person changes, why can't a habit?' -65
#4 2013-03-23 19:56:16
- Agnishom
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Re: Trigonometric Equation
Okay thanks I managed to understand this
'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'
'The whole person changes, why can't a habit?' -65
#5 2013-03-23 22:07:06
- bob bundy
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Re: Trigonometric Equation
hi Agnishom,
Glad you understand it. Your method and mine are essentially the same; I used k; you have t; and then I let k=1. In yours the t cancels out.
Bob
You cannot teach a man anything; you can only help him find it within himself..........Galileo Galilei
#6 2013-03-24 01:29:38
- Agnishom
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Re: Trigonometric Equation
Yeah Thanks! I had difficulty understanding the cancellation
'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'
'The whole person changes, why can't a habit?' -65
#7 2013-03-24 05:09:28
- bob bundy
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Re: Trigonometric Equation
Two triangles with sides in the same ratio are similar. So the angles are the same. Therefore you can just call t = 1 without losing any of the problem's conditions.
That's why it cancels out of the cosine rule step.
Bob
You cannot teach a man anything; you can only help him find it within himself..........Galileo Galilei