# Mathematics: Post your doubts here!

#### Thought blocker

Well whats big deal here?
Just replace the sin function with -1 that's all.
"Just replace sin 2t by -1"
Thats all in it.

Got it? Or want a work solution of whole 7th question?

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#### Thought blocker

Could someone please solve his for me:
The number of defect lamps found in every house has a Poisson distribution with mean 3.
a) Find the probability that for 7 particular houses, no defect lamps were found in 2 houses.
b) Find the probability that for 120 particular houses, at least 2 defect lamps were found in less than 70 houses
I haven't took Statistics. Sorry.

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Thanks a lot.

#### Farheen1201

Salam,
I need help with mechanics 1....Can somebody help?...
Chapter 4...
Question 7
A particle P of mass 4m kg is at rest on a horizontal table. A force of magnitude 50m Newtons acting upwards at an acute angle α to the horizontal, is applied to the particle. Given that tan α = (3/4) and that there is a resistance to the motion of magnitude 20m Newtons, find the acceleration with which P moves. Find in terms of m the magnitude of the normal contact force of the table on P.

#### Snowysangel

In s1, why is variance = [(sum of x2 + sum of y2)/ (x+y)] - (mean)2

#### Miral Lovato

Hey ! Amm is math compolsury in cie ? Lol i know it is but still if i can do some other subjects instead of this math mental math will really make me mental please tell me what can i do

#### The Godfather

In s1, why is variance = [(sum of x2 + sum of y2)/ (x+y)] - (mean)2
Sorry no S1 in my syllabus.

#### The Godfather

Hey ! Amm is math compolsury in cie ? Lol i know it is but still if i can do some other subjects instead of this math mental math will really make me mental please tell me what can i do
Why are you so afraid of mathematics?
It keeps our mind active and fresh.
I would suggest you to take mathematics. No other suggestion from my side.

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#### Thought blocker

Someone plz help me in this stupid confusing domain range chapter :/
If someone can help me understand ~Domain Range~ chapter and ~Vector Paper 3~ only, I would be really Thankful to him/her :/

Help needed!!!
I know that range of a function is the domain of the inverse function and vice versa but how to find domain in this question
part (iv) only
and PLZZ answer with deep knowledge ( I mean with more theory and working which is clearly understandable to solve rest of the questions):
Thanks and May Allah bless us all with knowledge and A/A*s in A Levels Ameen
View attachment 46644

kitkat <3 :P Angelina_25 shazmina fantastic girl Anyone :SSS
Plejj :'/
Here Rookaya did this. http://www.twiddla.com/1729925 Aly Emran

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