MATH HELP URGENT!!!!!!!!!!

[niassu]

IN THESE LINKS I need a good explaination to these questions
http://www.xtremepapers.net/CIE/Cambrid ... 9_qp_4.pdf
q6(a)(ii)
http://www.xtremepapers.net/CIE/Cambrid ... _qp_04.pdf
q5(e)and q10c(ii)
but I do not need vague answers
thanks in advance

 

[user]

Q6aii:The equation to solve is a quadratic eqn.A little tip i would like to pass is when the question just mentions to solve the eqn. that can be done using factorising method but if it says solve to 2dp the u can only solve it using the formula
hope u know the formula coz i cant write it as it contain square root and square any way if u dont know tell me will try out something!
how to factorize , x^2 + 5x – 36 = 0.well the eqn is in the form ax^2+bx+c=0
then find the product ac which is 1 x -36=-36
sum = b =+5 now find 2 factors of 36 one +ve and one -ve which give a sum of +5==>+9 & -4
now write the eqn again using these no. =>x^2+9x-4x-36 now factorise
x(x+9)-4(x+9)=0
(x-4)(x+9)=0

 

[PlanetMaster]

0581 May/June 09 Q6a(ii):
x² + 5x – 36 = 0
x² + 9x - 4x - 36 = 0
x(x+9) - 4(x+9) = 0
(x+9)(x-4) = 0

0581 Oct/Nov 08 Q5(e):
You need to calculate horizontal distance of A to C:
=60sin35 + 40sin80
=73.81km

0581 Oct/Nov 08 Q10c(ii):
Its a simple 'Arithmetic Progression'.
Use the formula for sum of terms:
S = (n/2) * [2a + (n-1)d]
S = (n/2) [2 + 2(n-1)]
S = n²

Clear?

 

[niassu]

sorry can u also explain q5(e) in this link
http://www.xtremepapers.net/CIE/Cambrid ... 9_qp_4.pdf
if u plz have also any thing about sequence formula can u give it to me
thanks very much in advance

 

[niassu]

plz is your expression about sum of sequence is true for any other sum of sequence.(planetmaster)