Mathematics: Post your doubts here!

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in part ii i am stuck at this step ..
Use the substitution now

ʃ5sin^3x*cos^2x dx

You have dx and u substitution

= ʃ 5sin^3x(u^2) (du/-sinx)

Cancelling out will give you,

=ʃ-5sin^2x(u^2)

Use trig identity : sin^2x = 1 – cos^2x

=-ʃ5(1 – cos^2x)(u^2)du

=-5ʃ(1 – u^2)(u^2)du

= -5ʃu^2 – u^4 du

=- 5 [(u^3/3) – (u^5/5)]

Put limits in.

-5 {[(1/3 – 1/5) – (0/3 – 0/5)]}

= -5 (2/15)

= -10/15

= -2/3

Area = 2/3 Ans.
*I think I messed up a sign somewhere or its the way it is :)
 
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I'm using this book :
http://www.amazon.com/Concise-Course-Advanced-Level-Statistics/dp/074875475X/ref=oosr
covers both S1 and S2
As for pastpapers, when I bought solved past papers, I had chosen S1 and M1 but later I changed my mind and found Statistics much more bearable than Mechanics, so I've solved papers for S1 but not for S2..But it doesn't matter, I'll print out unsolved ones and I can check them through mark schemes! What's your plan?
So aren't you having this book in pdf form or is it available for free online ?
Are there any solved papers for S2 ??? o_O ...if you have them then i need them urgently.
I have tried to use to use ms for S2 but it didnt work out for me bcz the method is not given in the ms :/
 
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I'm using this book :
http://www.amazon.com/Concise-Course-Advanced-Level-Statistics/dp/074875475X/ref=oosr
covers both S1 and S2
As for pastpapers, when I bought solved past papers, I had chosen S1 and M1 but later I changed my mind and found Statistics much more bearable than Mechanics, so I've solved papers for S1 but not for S2..But it doesn't matter, I'll print out unsolved ones and I can check them through mark schemes! What's your plan?
and one thing more ...does that book contains the topics such as cdf ,pdf , chi square etc ???
 
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So aren't you having this book in pdf form or is it available for free online ?
Are there any solved papers for S2 ??? o_O ...if you have them then i need them urgently.
I have tried to use to use ms for S2 but it didnt work out for me bcz the method is not given in the ms :/
Yes, the book is available online, check this website:
http://www.aliensservices.com/E-books.html

As for the solved papers, it's difficult, a mere chance, that they'll be available for S2, very few students choose S2, but I'll search and let you know if I find!
 
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and one this more ...does that book contains the topics such as cdf ,pdf , chi square etc ???
Yes, it does cover these, the probability density function and cumulative distribution function are covered in 6th unit, chi square must be there too and I can assure you, it covers ALL of the syllabus, and even more than that, soyou must keep checking the syllabus, like there is the one "Regression and Corrlation", that I haven't really found in syllabus so I skipped that.
 
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couldn't find .. i hope our answers are correct !
Listen. We are wrong. Why? because if you take note of your solution. You get the limit 1 when x is zero. and limit 0.5 when x is ln2. Observe how the position changes of both the values. Before transformation we have ln2 as the larger limit but when we calcute y we get 1/2 which is the smaller value in the transformation. Therefore, When this happens, The sign of the expression can change :)
 
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Listen. We are wrong. Why? because if you take note of your solution. You get the limit 1 when x is zero. and limit 0.5 when x is ln2. Observe how the position changes of both the values. Before transformation we have ln2 as the larger limit but when we calcute y we get 1/2 which is the smaller value in the transformation. Therefore, When this happens, The sign of the expression can change :)
Ohh ! i didnt know about this points . BTW thanks :) (Y)
 
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