Author Topic: Trigonometry  (Read 4936 times)

nid404

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Trigonometry
« on: September 08, 2009, 04:23:37 am »
Express 8 sin theta-15 cos theta in the form R sin(theta-alpha), where R > 0 and 0degress < alpha < 90degrees, giving the
exact value of R and the value of alpha correct to 2 decimal places.

Can somebody help me with this....plz guide me with the steps..astar plz help

« Last Edit: September 08, 2009, 04:44:43 am by nid404 »

nid404

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Re: Trigonometry
« Reply #1 on: September 08, 2009, 04:54:43 am »
one more identity question...it's a little complicated for me to understand
Prove the identity
(cos x + 3 sinx)2 = 5 - 4cos2x + 3 sin2x.

Sir, can u list all the equations we need to know for AS trig...i mean equations relating the three functions (tan,sin and cos)
« Last Edit: September 08, 2009, 06:08:55 am by nid404 »

Offline Ghost Of Highbury

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Re: Trigonometry
« Reply #2 on: September 08, 2009, 05:53:40 am »
one more identity question...it's a little complicated for me to understand
Prove the identity
(cos x + 3 sinx)2 ? 5 ? 4cos2x + 3 sin2x.

Sir, can u list all the equations we need to know for AS trig...i mean equations relating the three functions (tan,sin and cos)

wats the '?'.........
divine intervention!

nid404

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Re: Trigonometry
« Reply #3 on: September 08, 2009, 06:08:13 am »
one more identity question...it's a little complicated for me to understand
Prove the identity
(cos x + 3 sinx)2 ? 5 ? 4cos2x + 3 sin2x.

Sir, can u list all the equations we need to know for AS trig...i mean equations relating the three functions (tan,sin and cos)

wats the '?'.........
oopss....when i copy pasted it...the symbol changed...anyways i've corrected it

master786

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Re: Trigonometry
« Reply #4 on: September 08, 2009, 06:09:14 am »
ur question can u clear it nd post ...
i cant get the question properly ... the second tht is ...

nid404

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Re: Trigonometry
« Reply #5 on: September 08, 2009, 06:10:16 am »
ur question can u clear it nd post ...
i cant get the question properly ... the second tht is ...

yup it's correct now
Can you answer it master786??
« Last Edit: September 08, 2009, 06:21:20 am by nid404 »

Offline Ghost Of Highbury

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Re: Trigonometry
« Reply #6 on: September 08, 2009, 06:25:21 am »
one more identity question...it's a little complicated for me to understand
Prove the identity
(cos x + 3 sinx)2 = 5 - 4cos2x + 3 sin2x.

Sir, can u list all the equations we need to know for AS trig...i mean equations relating the three functions (tan,sin and cos)

is it 4cos2x and 3sin2x...or 2x
divine intervention!

master786

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Re: Trigonometry
« Reply #7 on: September 08, 2009, 06:26:15 am »
i wil ltry :P

lost touch with identities .. is this C2 stuff ?
or higher ?

nid404

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Re: Trigonometry
« Reply #8 on: September 08, 2009, 06:31:41 am »
i wil ltry :P

lost touch with identities .. is this C2 stuff ?
or higher ?

It's an AS question Pure maths

master786

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Re: Trigonometry
« Reply #9 on: September 08, 2009, 06:32:31 am »
oh great lets wait for astar :P
he wil answer it in no time :)

nid404

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Re: Trigonometry
« Reply #10 on: September 08, 2009, 06:33:37 am »
one more identity question...it's a little complicated for me to understand
Prove the identity
(cos x + 3 sinx)2 = 5 - 4cos2x + 3 sin2x.

Sir, can u list all the equations we need to know for AS trig...i mean equations relating the three functions (tan,sin and cos)

is it 4cos2x and 3sin2x...or 2x

2x not superscript

haha master786 i knew astar could do it :P

master786

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Re: Trigonometry
« Reply #11 on: September 08, 2009, 06:39:07 am »
yea :P i hav done identities but inedexcel...C2 ..theC3 once might be the level of pure maths ... nd C3 i havent done yet :P
so yea astars the man now :P

nid404

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Re: Trigonometry
« Reply #12 on: September 08, 2009, 06:45:28 am »
yea :P i hav done identities but inedexcel...C2 ..theC3 once might be the level of pure maths ... nd C3 i havent done yet :P
so yea astars the man now :P

no problem master...i can wait

Offline Ghost Of Highbury

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Re: Trigonometry
« Reply #13 on: September 08, 2009, 06:59:50 am »
one more identity question...it's a little complicated for me to understand
Prove the identity
(cos x + 3 sinx)2 = 5 - 4cos2x + 3 sin2x.

Sir, can u list all the equations we need to know for AS trig...i mean equations relating the three functions (tan,sin and cos)

done
answer in the next post
divine intervention!

nid404

  • Guest
Re: Trigonometry
« Reply #14 on: September 08, 2009, 07:01:09 am »
one more identity question...it's a little complicated for me to understand
Prove the identity
(cos x + 3 sinx)2 = 5 - 4cos2x + 3 sin2x.

Sir, can u list all the equations we need to know for AS trig...i mean equations relating the three functions (tan,sin and cos)

done
answer in the next post

Thanks adi...