Mathematics: Post your doubts here!

[farhan141]

No I divided by x on both sides.
I justified this by reminding that x>0 so it cannot be equal to zero.
If you divide zero on both sides you can run into all sorts of trouble. But as long as x is not zero you can divide on both sides like that.
Or you can think of it as just factoring out x. Then the second bracket can be equated to zero as well.

Whole 5 and 6 question.

Also please do both integration ones from the previous ones i uploaded. Thanks for the others, will look into it in a while then will let u know

 

[osama ahmed ibrahim]

help in part ii
i didnt take log function so how they expect me to use it
also i cant understand the answer help me i always leave this q blank
i want clear explanation and an alternative to log function if possible in part II

 

[osama ahmed ibrahim]

also i cant understand what q wants in part ii

 

[Wkhan860]

http://papers.gceguide.com/A Levels/Mathematics (9709)/9709_s13_qp_63.pdf

Question 7(iii) please.

Rizwan Javed

 

[Rizwan Javed]

http://papers.gceguide.com/A Levels/Mathematics (9709)/9709_s13_qp_63.pdf

Question 7(iii) please.

Rizwan Javed

Consider poodles are represented by 'O'
and spaniels and retrievers both are represent by *
the way they can be arranged such that no poodle is together is:
O * O * O * O * O

Now arrange the spaniels and retrievers in their places represent by *. This will be done in 4! ways.

Now from the 5 possible places of poodles, you are to select 3 since there are 3 poodles. So select these places 5C3. Now 3 poodles can be arranged in their selected places in 3! ways.

So the total no. of possible arrangement are:

4! * 5C3 * 3! = 1440 Ans.

 

[Wkhan860]

Consider poodles are represented by 'O'
and spaniels and retrievers both are represent by *
the way they can be arranged such that no poodle is together is:
O * O * O * O * O

Now arrange the spaniels and retrievers in their places represent by *. This will be done in 4! ways.

Now from the 5 possible places of poodles, you are to select 3 since there are 3 poodles. So select these places 5C3. Now 3 poodles can be arranged in their selected places in 3! ways.

So the total no. of possible arrangement are:

4! * 5C3 * 3! = 1440 Ans.

Thanks!

Same paper qtn 4 part (ii)
The MS says that we have to use continuity correction here but theres no mention of the word approximation in the question. Why is that?

 

[Rizwan Javed]

Thanks!

Same paper qtn 4 part (ii)
The MS says that we have to use continuity correction here but theres no mention of the word approximation in the question. Why is that?

Though the question doesnot state this, but since you are using NORMAL APPROXIMATION to solve a question which involves a binomial distrbution you'll have to do continuity correction.

 

[Wkhan860]

Though the question doesnot state this, but since you are using NORMAL APPROXIMATION to solve a question which involves a binomial distrbution you'll have to do continuity correction.

But we do not use continuity correction in ever normal distribution question. So why so in this case?

 

[Rizwan Javed]

But we do not use continuity correction in ever normal distribution question. So why so in this case?

We don't use continuity correction only when it is stated in the question that a certain variable follows a normal distribution. Otherwise, if YOU are using normal distribution to make an approximation for any other distribution like binomial , you have to use continuity correction.

 

[osama ahmed ibrahim]

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help in part ii
i didnt take log function so how they expect me to use it
also i cant understand the answer help me i always leave this q blank

 

[osama ahmed ibrahim]

also i cant understand what q wants in part ii
View attachment 60261
View attachment 60260

Rizwan Javed qwertypoiu
help please

 

[Rizwan Javed]

also i cant understand what q wants in part ii
View attachment 60261
View attachment 60260

In part (ii) you are required to prove the inequality.

0<θ<90 means that it lies in the first quadrant. In the first quadrant, sinθ is always positive i.e. sinθ>0. Similarly, tanθ is also greater than 0 in the first quadrant. tanθ>0

If both are greater than 0, then from the identity given above, you can predict this that
tan^2θ * sin^2θ will be also be greater than 0.
So if the RHS ( tan^2θ * sin^2θ ) of the identity is greater than zero, the LHS would also be greater than 0. So, just solve the inequality now:

tan^2θ - sin^2θ > 0
take sin^2θ on the RHS of the inequality
tan^2θ > sin^2θ
take square root on both sides, and you'll end up with:
tanθ > sinθ

 

[i_try9621]

Hey guys.
Can someone please help me with this question
View attachment 60208

I got the answer for the first part
View attachment 60209

But the problem is i don't get why did they not calculate mg sinθ as resistive force in the second part although they used it in the first part of the question. The engine would also do work against this component of weight so why dont we use it in our calculation.
View attachment 60210
please help....

I think that the component of weight parallel to the slope for a distance of 500 metres is the gain in Potential Energy . Because if you notice, ''mgsinθ'' times ''500'' is 375000 J. And the gain in Potential energy is "mg" times "500sinθ" is also 375000 J. Although I may not be sure...

 

[The Sarcastic Retard]

View attachment 60259 View attachment 60258
help in part ii
i didnt take log function so how they expect me to use it
also i cant understand the answer help me i always leave this q blank
i want clear explanation and an alternative to log function if possible in part II

No other way I know.
Its the only way.
Learn log rules. Its easy as anything could be

 

[osama ahmed ibrahim]

No other way I know.
Its the only way.
Learn log rules. Its easy as anything could be

can u forward a link for it please
video for log function which will then help in this q

 

[osama ahmed ibrahim]

Need notes for permutation and combination

 

[techgeek]

One of the integration questions...

Spoiler

View attachment 60254

 

[The Sarcastic Retard]

can u forward a link for it please
video for log function which will then help in this q

can u forward a link for it please
video for log function which will then help in this q

Chapter 2

 

[farhan141]

One of the integration questions...

Spoiler

View attachment 60254

The other integration one please and

Whole 5 and 6 question.

Also please do both integration ones from the previous ones i uploaded. Thanks for the others, will look into it in a while then will let u know

 

[areeba240]

how to solve the last two parts i.e. (b) and (c) of this qtn...plzzzzz helppppp
thanks in advance