Author Topic: IMPORTANTTT  (Read 2572 times)

Offline Saladin

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Re: IMPORTANTTT
« Reply #15 on: August 07, 2010, 11:47:41 am »
Let me get this straight, are your values as follows?

sin(p)=\frac{2}{3} and \frac{\pi}{2}=p

Offline Saladin

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Re: IMPORTANTTT
« Reply #16 on: August 07, 2010, 11:53:10 am »
Would you be kind enough to give the .pdf file of the question in concern?

Offline cooldude

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Re: IMPORTANTTT
« Reply #17 on: August 07, 2010, 05:18:27 pm »
if sin p = 2/3  and                   pie/2 <= p <= pie                , then tan p is equal to

A) -2/sqrt 5
B)  2 / sqrt 13
c) sqrt 5/2
D)- 1 /sqrt 13
E) 2/sqrt 5


sin p=2/3
(sin p)^2+(cos p)^2=1
cos p=root 1-(4/9)=root 5/9
tan p=sin p/cos p=2/3 / (root 5)/3
=2/root 5 therefore e

Offline mousa

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Re: IMPORTANTTT
« Reply #18 on: August 07, 2010, 05:25:53 pm »
yepppp  ;D ;D ;D
u heading there 2 ?

I might. I  have done all placement tests.Though i applied for medicine aswell,  but still not confirmed till the results are out!!!

By the way, when is your placement test??

Offline halosh92

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Re: IMPORTANTTT
« Reply #19 on: August 08, 2010, 07:40:47 pm »
hey engraved nop its  hard copy actually :S

one more question:

cos( 5pie/4) is equal to
a) -1
b) 1/2
c) -1/2
d) -1/sqrt2
e) none of these
is it e ???


another question:

find all the solutions of the equation    sin(2x)= 1
given that x is in the interval (0, 2 pie)\
a) pie/2 only
b) pie/4 only
c) pie/4 and 3pie/4
d) pie/4 and 5pie/4
e) none of these.
thxxxx cool dude By the way xD
« Last Edit: August 08, 2010, 07:49:31 pm by halosh92 »
everyday we wake up is a miracle, then how do we say miracles dont happen?????

Offline Saladin

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Re: IMPORTANTTT
« Reply #20 on: August 08, 2010, 09:10:16 pm »
For the first Question:

The answer is (e). cos(\frac{5\pi}{4}) basically means that the value is a negative version of cos(0.25\pi). Because up till \frac{\pi}{2} the values for cos are positive, as it is in the ALL quadrant. However, this does not lie in that quadrant, so it is negative version of cos(\frac{\pi}{4}).

For the second question:

The only answer is (c).

sin(2x)=1

2x=90

x=45 or \frac{\pi}{4} (I like working in degrees)

Remembering the sin wave, by making the equation y=sin(2x), you put two sin waves into the 0 to 360 gap. Therefore, where 360 degrees was, that position is 180 degrees. Therefore, if we repeat the wave, we repeat the values. Therefore 180+45=225 degrees is also an answer.

So, the two answers are:

\frac{\pi}{4} and \frac{3\pi}{4}

The working without the explanation is as follows:

sin(2x)=1

 2x=90

 2x=450

Therefore, x=45 and x=225

45 degrees is equal to \frac{\pi}{4} radians and 225 degrees is equal to \frac{3\pi}{4}

Hope this clears all doubts.
« Last Edit: August 08, 2010, 09:30:45 pm by Engraved »

Offline halosh92

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Re: IMPORTANTTT
« Reply #21 on: August 09, 2010, 06:07:19 am »
For the first Question:

The answer is (e). cos(\frac{5\pi}{4}) basically means that the value is a negative version of cos(0.25\pi). Because up till \frac{\pi}{2} the values for cos are positive, as it is in the ALL quadrant. However, this does not lie in that quadrant, so it is negative version of cos(\frac{\pi}{4}).

For the second question:

The only answer is (c).

sin(2x)=1

2x=90

x=45 or \frac{\pi}{4} (I like working in degrees)

Remembering the sin wave, by making the equation y=sin(2x), you put two sin waves into the 0 to 360 gap. Therefore, where 360 degrees was, that position is 180 degrees. Therefore, if we repeat the wave, we repeat the values. Therefore 180+45=225 degrees is also an answer.

So, the two answers are:

\frac{\pi}{4} and \frac{3\pi}{4}

The working without the explanation is as follows:

sin(2x)=1

 2x=90

 2x=450

Therefore, x=45 and x=225

45 degrees is equal to \frac{\pi}{4} radians and 225 degrees is equal to \frac{3\pi}{4}

Hope this clears all doubts.

thankyouuuu yes very clear :D
everyday we wake up is a miracle, then how do we say miracles dont happen?????

Offline Saladin

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Re: IMPORTANTTT
« Reply #22 on: August 09, 2010, 02:05:44 pm »
thankyouuuu yes very clear :D

Glad to be of service! :)