Mathematics: Post your doubts here!

[Suchal Riaz]

Guys I need help on this!

Cos(x-1/4pi)=0
Cos is zero at 1/2pi or -1/2p so
X-1/4pi=-1/2pi or 1/2pi
x=-1/4pi or 3/4pi
X=3/4pi can't be a solution as it is out of range.
So x=-1/4pi

 

[Ahmed Aqdam]

this is one of the typical questions of probability but the remaining probability which makes my total probability equals to one is of the case in which the match draws when 2/3/4/5 matches are played and also we have to include the probability of both players winning

The match cannot be drawn and the other player winning would have the reverse order and would have no effect on the probability so that does not have to be included.

 

[Deepro]

Does anyone have the Pure Mathematics 1 formula sheet?
If so, please share

 

[Suchal Riaz]

Does anyone have the Pure Mathematics 1 formula sheet?
If so, please share

It is at the end of syllabus. I have printed many sheets which are found everywhere in my bag and my table. But i rarely need it. But when you are doing further math or P3 you will need to look at it as a normal person does not learn all the formulas.

 

[Deepro]

It is at the end of syllabus. I have printed many sheets which are found everywhere in my bag and my table. But i rarely need it. But when you are doing further math or P3 you will need to look at it as a normal person does not learn all the formulas.

Okay, thanks

 

[Manobilly]

q10part b ,how will we find the 6 roots?

 

[Manobilly]

Also 33/M/J/11Q7 part iii

 

[Lyfroker]

Yes

Will we be asked to sketch a tangent graph?? :S

 

[Talha Irfan]

This question is not from past papers it's from advanced level statistics by J.crawshaw and chambers.
Page no
Page 377 q6 and 9.
Q6)bags of flour packed by a particular machine have masses which are normally distributed with mean of 500g and standard deviation of 20g.2% of the bags are rejected for being underweight and one percent of the bags are rejected for being overweight?between what range of values should the mass of a bag of flour lie if it has to be accepted.


Q9)mean=400 and standard deviation is 8
A)find the limits within which the central 95% of the distribution lies.
B)find the inter quartile range of the distribution.



Plz solve these questions.thanks a lot!!

Hope it helps

 

[Fatima M.S. Alimohamed]

Guys I need help on this!

0= cos x + sin x
cos x = -sin x
divide both sides by cos x
1= -sin x/cos x
1= -tan x
x= -1/4 pie

 

[Suchal Riaz]

Will we be asked to sketch a tangent graph?? :S

Yes we can be asked. But more chances are that graph is drawn and you will need to write it's equation. Or equation and sketch of equation are given and you are required to fibd value of A or B points on graph. Such as point where y=2tan(X)-1 touches X-axis first time left of origin.

 

[M Haseeb Javed]

9709 w12 61 question 6 part 2

------------------------
6 Ana meets her friends once every day. For each day the probability that she is early is 0.05 and the
probability that she is late is 0.75. Otherwise she is on time.

(ii) If she is early there is a probability of 0.7 that she will eat a banana. If she is late she does not
eat a banana. If she is on time there is a probability of 0.4 that she will eat a banana. Given that
for one particular meeting with friends she does not eat a banana, find the probability that she is
on time. [4]

-----------------------------------

 

[Talha Irfan]

9709 w12 61 question 6 part 2

------------------------
6 Ana meets her friends once every day. For each day the probability that she is early is 0.05 and the
probability that she is late is 0.75. Otherwise she is on time.


(ii) If she is early there is a probability of 0.7 that she will eat a banana. If she is late she does not
eat a banana. If she is on time there is a probability of 0.4 that she will eat a banana. Given that
for one particular meeting with friends she does not eat a banana, find the probability that she is
on time. [4]

-----------------------------------

This is a conditional probability question

P(Anna is on time l Anna doesn't eat banana)

= P(Anna is on time AND Anna doesn't eat banana) / P(Anna doesn't eat banana)
= (0.2(on time probability) * 0.6 (probability of not eating banana when she is on time) / ((0.6*0.2) + (0.05*0.3) + (0.75*1))

= 0.136

 

[Lyfroker]

Yes we can be asked. But more chances are that graph is drawn and you will need to write it's equation. Or equation and sketch of equation are given and you are required to fibd value of A or B points on graph. Such as point where y=2tan(X)-1 touches X-axis first time left of origin.

Ok thnx

 

[M Haseeb Javed]

?

 

[M Haseeb Javed]

This is a conditional probability question

P(Anna is on time l Anna doesn't eat banana)

= P(Anna is on time AND Anna doesn't eat banana) / P(Anna doesn't eat banana)
= (0.2(on time probability) * 0.6 (probability of not eating banana when she is on time) / ((0.6*0.2) + (0.05*0.3) + (0.75*1))

= 0.136

Why do we use "dosnt eat banana" ? are we free to use "ate banana" ?

 

[Talha Irfan]

Why do we use "dosnt eat banana" ? are we free to use "ate banana" ?

no, we're not. We have to do what question says. It asked about the case when she doesn't eat banana so we have to make our conditional probability statement according to that and solve likewise. (i.e probability that she is on time given that she doesn't eat a banana)

 

[Talha Irfan]

View attachment 36855

?

Solution to your second query

 

[Manobilly]

I posted a doubt above,plz solve it anyone?

 

[M Haseeb Javed]

Solution to your second query

Thanks!