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Author Topic: c2 DOUBT  (Read 2390 times)

Offline Igcseboy

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c2 DOUBT
« on: April 29, 2010, 01:14:19 pm »
Jan 2007 question 9 c

and June 2007 question 9 a and b

They are from edexcel mathmetics C2

anyones help will be apprecited

thanxxx
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Offline Saladin

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Re: c2 DOUBT
« Reply #1 on: April 29, 2010, 01:19:28 pm »
In 30 minutes.
« Last Edit: April 29, 2010, 01:32:35 pm by The Dude 321 »
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Offline astarmathsandphysics

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Re: c2 DOUBT
« Reply #2 on: April 30, 2010, 12:22:16 am »
When i get up
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Offline halosh92

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Re: c2 DOUBT
« Reply #3 on: April 30, 2010, 09:38:08 am »
could someone please solve this:

simplify the expression:

sin^4 thita  +   2sin^2 thita cos^2 thita + cos^4 thita
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everyday we wake up is a miracle, then how do we say miracles dont happen?????

Offline SGVaibhav

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Re: c2 DOUBT
« Reply #4 on: April 30, 2010, 09:45:03 am »
do u mean this     

USING X instead of thita
sin^4(x) + 2sin^2(x)cos^2(x) + cos^4(x)
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Offline Saladin

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Re: c2 DOUBT
« Reply #5 on: April 30, 2010, 09:48:08 am »
It is simply
(sin^2\theta+cos^2\theta)^2
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Offline SGVaibhav

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Re: c2 DOUBT
« Reply #6 on: April 30, 2010, 09:52:18 am »
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Offline Saladin

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Re: c2 DOUBT
« Reply #7 on: April 30, 2010, 09:56:35 am »
I was getting to that  :P
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Offline SGVaibhav

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Re: c2 DOUBT
« Reply #8 on: April 30, 2010, 09:58:01 am »
Solving Again

Question is
sin^4\theta+ 2(sin^2\theta cos^2\theta)+cos^4\theta

Which is equal to
(sin^2 \theta + cos^2 \theta )^2

And the identity
sin^2\theta+cos^2\theta = 1

Therefore the Answer is
(1)^2 = 1

=)
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Offline halosh92

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Re: c2 DOUBT
« Reply #9 on: April 30, 2010, 10:28:33 am »
yes thankyou both very much :)
could u please solve this too:
find:
sin (x) and cos(x) , given that tan (x)=5/12 and that (x) is acute

thx
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Offline astarmathsandphysics

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Re: c2 DOUBT
« Reply #10 on: April 30, 2010, 10:33:43 am »
tan x =5/12 =o/a
h=sqrt(o^2 +a^2)=sqrt(5^2+12^2)=13
cos x=a/h =12/13
sin x= o/h=5/13
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Offline halosh92

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Re: c2 DOUBT
« Reply #11 on: April 30, 2010, 10:39:06 am »
Quote from: astarmathsandphysics on April 30, 2010, 10:33:43 am
tan x =5/12 =o/a
h=sqrt(o^2 +a^2)=sqrt(5^2+12^2)=13
cos x=a/h =12/13
sin x= o/h=5/13

thx :)
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everyday we wake up is a miracle, then how do we say miracles dont happen?????

Offline astarmathsandphysics

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Re: c2 DOUBT
« Reply #12 on: April 30, 2010, 11:22:04 am »
no probs. so many asking questions atm. I will be here for next few hours at least.
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Offline halosh92

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Re: c2 DOUBT
« Reply #13 on: April 30, 2010, 12:16:02 pm »
solve the equations for thita. in the interval 0<thita<360 :
sin thita + cos thita=0
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everyday we wake up is a miracle, then how do we say miracles dont happen?????

Offline astarmathsandphysics

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Re: c2 DOUBT
« Reply #14 on: April 30, 2010, 12:32:51 pm »
Take cos theta to the right and divide by cos theta to get tan theta=-1 so theta =-45 the keep adding 180 to get 135 and 315
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