Mathematics: Post your doubts here!

[Hamzeh S]

i got nvm !

 

[always-smile :)]

plzzzzz URGENT HELP IN THIS
http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Mathematics (0580)/0580_w09_qp_4.pdf
NUMBER 7)C)I & II

q7 c i ) use the same formula of volume of cone but use (3r)^2 instead of r^2 and use (3h) instead of h
it will be --> 1/3 x pie x (3r)^2 x 3h ---->1/3 x pie x 9r^2 x 3h -----> notice that --> 1/3 x pie x r^2 x h x 27 is equal to 1/3 x pie x 9r^2 x 3h SO equal 27 W

c ii ) use the same way as i
use the same formula of volume then instead of r^2 put (2x)^2 and instead of h put y
it will be --> 1/3 x pie x (2x)^2 x y ---> 1/3 x pie x 4x^2 x y ----> 4/3 x pie x x^2 x y ---->notice that --> 4(1/3) x pie x x^2 x y equals to 1/3 x pie x 4x^2 x y SO equals 4W

 

[always-smile :)]

i got nvm !

that's fine

 

[Razo513]

q7 c i ) use the same formula of volume of cone but use (3r)^2 instead of r^2 and use (3h) instead of h
it will be --> 1/3 x pie x (3r)^2 x 3h ---->1/3 x pie x 9r^2 x 3h -----> notice that --> 1/3 x pie x r^2 x h x 27 is equal to 1/3 x pie x 9r^2 x 3h SO equal 27 W

c ii ) use the same way as i
use the same formula of volume then instead of r^2 put (2x)^2 and instead of h put y
it will be --> 1/3 x pie x (2x)^2 x y ---> 1/3 x pie x 4x^2 x y ----> 4/3 x pie x x^2 x y ---->notice that --> 4(1/3) x pie x x^2 x y equals to 1/3 x pie x 4x^2 x y SO equals 4W

what i didnt get is how did we consider 1/3 x pie x r^2 x h x 27 is equal to 1/3 x pie x 9r^2 x 3h SO equal 27 W???

 

[always-smile :)]

what i didnt get is how did we consider 1/3 x pie x r^2 x h x 27 is equal to 1/3 x pie x 9r^2 x 3h SO equal 27 W???

take 9 and 3 out of the equation to bring it back to its previous form then multiply all by 27 which is 9 by 3
you can check it if you make substitution with values of r and h in both equation (( i mean 1/3 x pie x 9r^2 x 3h and 1/3 x pie x r^2 x h x 27 )) and it will give you the same answer

 

[Razo513]

take 9 and 3 out of the equation to bring it back to its previous form then multiply all by 27 which is 9 by 3
you can check it if you make substitution with values of r and h in both equation (( i mean 1/3 x pie x 9r^2 x 3h and 1/3 x pie x r^2 x h x 27 )) and it will give you the same answer

THANK U SOOO MUCH

 

[always-smile :)]

THANK U SOOO MUCH

no need ur welcome
any more questions?? or i can log out?

 

[Razo513]

no need ur welcome
any more questions?? or i can log out?

u can log out thx again

 

[always-smile :)]

u can log out thx again

ok good night and no need for thanx it's ok

 

[сᴏᴏʟ сяуѕтᴀʟѕ]

Thank u so much coolio!!

its okie..juss remember me in your prayers

 

[sma786]

OMG You're amaaaaaazing !! thanks soo much.. cudnt hav understood it any better thanks again

 

[sma786]

http://www.xtremepapers.com/CIE/Cambridge IGCSE/0580 - Mathematics/0580_w10_qp_22.pdf
.. Help ! Question 7 (c) and (d)

 

[princessanum]

its okie..juss remember me in your prayers

u r always in ma prayers..

 

[princessanum]

http://www.xtremepapers.com/CIE/Cambridge IGCSE/0580 - Mathematics/0580_w10_qp_22.pdf
.. Help ! Question 7 (c) and (d)

u have posted the wrong link!!

 

[sma786]

u have posted the wrong link!!

http://www.xtremepapers.com/CIE/Cambridge IGCSE/0580 - Mathematics/0580_w10_qp_42.pdf ...

 

[GetSomeLife]

http://www.xtremepapers.com/CIE/Cambridge IGCSE/0580 - Mathematics/0580_w10_qp_42.pdf ...

These is no C and D part of this

 

[sma786]

These is no C and D part of this

ok lol forget it

 

[sma786]

Any1 knows this ?? Question 10,c (ii)

http://www.xtremepapers.com/CIE/Cambridge IGCSE/0580 - Mathematics/0580_w10_qp_42.pdf

 

[NIM]

Learn these 2 formulas:

1) This formula can only be applied if the difference is constant between the first and the second, second and third etc.
nth term = a + d (n - 1)
where:
'a' is the FIRST term
'd' is the DIFFERENCE between the terms


2) This formula can only be applied if, in simple terms, the first term is multiplied by a number to get the second term... and the second term is multiplied by the same number to get the third and so on:
nth term = ar^(n-1)
'a' is the FIRST term
'r' is the number they are being multiplied with
1, 2, 4, 8, 16 (for instance)
1*2^(n-1)
= 2^(n-1) Answer


There are many questions you can't solve even when you know these sequences. For that, you need to use some common sense and the sequences already given

dude how abut "adding numbers with sequence"....
what should b the formula fr that one........

 

[kboss]

Any1 knows this ?? Question 10,c (ii)

http://www.xtremepapers.com/CIE/Cambridge IGCSE/0580 - Mathematics/0580_w10_qp_42.pdf

its quite simple:
1) make 3 eqns. (since there are 3 variables)
2) they are:
a) -33+x=y
b) x+y=z
c) y+z=18
3) then replace y with -33 + x
i.e. x + -33 + x= z
and -33 + x + z =18
4) reorder and make it into a simultaneous eqn.
i.e. 2x-z=33 and x +z = 51
5) solve the eqn.
6) u will get the value of x, = 28
7) then put the value of x (28) in the first eqn. (a)
8) u will get y as -5
9) then put the value of y (-5) in the last eqn. (c)
10) u will get z as 23

so there u have it
hope it helps and best of luck!!!