Maths, Addmaths and Statistics: Post your doubts here!

[robinhoodmustafa]

This is in our book as well. It is very brain draining since it involves using a number of right-angled triangles and assumptions to calculate the vectors. Questions like these don't come in CIE for obvious reasons.
http://mathforum.org/library/drmath/view/55029.html
I searched and found this solution. Hope it helps.

How many different 4 digits numbers greater than 3000 can be formed using the six digits 1,2,,3,4,5,6,if no digit can be used more than once..

So i know we would make 4 dashes and select the number but how do we choose the digits ?? Explain me please

 

[mohdumar]

How many different 4 digits numbers greater than 3000 can be formed using the six digits 1,2,,3,4,5,6,if no digit can be used more than once..

So i know we would make 4 dashes and select the number but how do we choose the digits ?? Explain me please

Greater than 3000 means first digit can be 3,4,5,6 i.e. 4 options

rest 5 digits remain from which three digits need to be permuted

4*5P3=240

 

[robinhoodmustafa]

Greater than 3000 means first digit can be 3,4,5,6 i.e. 4 options

rest 5 digits remain from which three digits need to be permuted

4*5P3=240

But 3,4,5,5 are lesser than 3000 ?

 

[Talha Irfan]

This is in our book as well. It is very brain draining since it involves using a number of right-angled triangles and assumptions to calculate the vectors. Questions like these don't come in CIE for obvious reasons.
http://mathforum.org/library/drmath/view/55029.html
I searched and found this solution. Hope it helps.

Thanks Alot Btw

 

[Talha Irfan]

this is such a diificult question that my sir said to award Rs 100 to the one who solves it correctly!

Here's The Solution Provided By Saad Mughal http://mathforum.org/library/drmath/view/55029.html Enjoy Rs. 100

 

[Saad Mughal]

How many different 4 digits numbers greater than 3000 can be formed using the six digits 1,2,,3,4,5,6,if no digit can be used more than once..

So i know we would make 4 dashes and select the number but how do we choose the digits ?? Explain me please

You could either SUBTRACT the possibility of numbers less than 3000 from all the choices.
Or you could set the first digit from any of the following; 3,4,5,6.
The two methods are:
All choices = 6P4 = 360
Less than 3000 = 2 * 5P3 = 120
Number of digits = 360 - 120 = 240.

OR,
The first digit can be either 3,4,5,6, so,
Number of digits = 4 * 5P3 = 240.

 

[simranlalchand]

can anyone answer Q7 part i of 4037 w12qp12?

 

[Talha Irfan]

can anyone answer Q7 part i of 4037 w12qp12?

You can solve by either similarity and congruence or by equations
For equations : -
STEP
1 : - Find gradient of AB
2 : -Use the gradient to find equation of DC ( Parallel, gradient same)
3: - Find equation of EB
4: - Find the gradient of AE by perpendicular gradient method m1 x m2 = -1
5: - Find equation of AE
6: - Simultaneously Solve AE And DC equations And BE And AE equations to get the points D And E

 

[simranlalchand]

the gradient of AB is coming 0 and we know that D(x,8) so how can i get the value of x

 

[Talha Irfan]

the gradient of AB is coming 0 and we know that D(x,8) so how can i get the value of x

you cant find this way, as i told u find equations and solve them, simple
the line CD would be y=8 as u can see

 

[sj0007]

the gradient of AB is coming 0 and we know that D(x,8) so how can i get the value of x

find gradient BE using the coordinates of B and C......then find gradient of AE by the fact that BE and AE are perpendicular....the gradient of AE is equal to the gradient of AD...so substitute the coordinates of A(-5,4) and D (x,8) into the gradient formula and equate it tho the gradient of AE wich will be 0.5.....thus u'll get the value of the x coordinate of D.....if u still can't understand tell me i will try to explain you by another method..gud luck!!

 

[sj0007]

you cant find this way, as i told u find equations and solve them, simple
the line CD would be y=8 as u can see

u can....there is an alternative way of solving it...i explained it above....

 

[simranlalchand]

you cant find this way, as i told u find equations and solve them, simple
the line CD would be y=8 as u can see

thank you very much i got the answer

 

[Talha Irfan]

thank you very much i got the answer

pleasure - And yeah pray for me too

 

[Talha Irfan]

u can....there is an alternative way of solving it...i explained it above....

Another alternative is through similarity and congruence, it's precise through it

 

[sj0007]

Another alternative is through similarity and congruence, it's precise through it

wat about the method i used ??

 

[Talha Irfan]

wat about the method i used ??

That's Also Correct

 

[Talha Irfan]

this is such a diificult question that my sir said to award Rs 100 to the one who solves it correctly!

Help Bro ;
At 12 00 hours, a ship has position vector (54i + 16j) km relative to a lighthouse, where i is
a unit vector due East and j is a unit vector due North. The ship is travelling with a speed of
20 km h in the direction 3i +4j.
(i) Show that the position vector of the ship at 15 00 hours is (90i + 64j) km. [2]

 

[sj0007]

Help Bro ;
At 12 00 hours, a ship has position vector (54i + 16j) km relative to a lighthouse, where i is
a unit vector due East and j is a unit vector due North. The ship is travelling with a speed of
20 km h in the direction 3i +4j.
(i) Show that the position vector of the ship at 15 00 hours is (90i + 64j) km. [2]

its pretty simple....use the direction vector of ship to find its direction in degrees....it will be 53.13.....use this to find out the velocity vector of 20 km/h.......

the position vector at 1500 hours would be the initial position vector at 1200 54i + 16j + the distance travelled in the 3 hrs( 3*velocity vector of 20 km/h)
hope i helped!!

 

[simranlalchand]

what is the area of trapezium?