Need help!!!

[Qamar]

Zohaib bhai plzz help...how to make "nth"term???

 

[Zishi]

If there's a common difference between every term, then this is the formula:

nth term= a + [(n-1)xd]

Where a= first term of that sequence, d=common difference between all terms.

As for the other sequences, we've to apply our mind by watching the terms in a sequence again and again.

 

[M.Usman Khan]

agreed ....there is another formula for some multiples or something....but thats a-level stuff....

best way is to stare at the sequence and try to find the pattern....according to teachers it will just pop in(may the force b with u) :lol:

 

[emkay]

you can also look at this one,
Un = an + b

where,
U= Unknown term
n= Position in sequence
a= Common Difference
b= Constant

for example,
Q: Calculate U100 of the following sequence,
4,7,10,13,16

Solution:
Un = an + b
U100 = 3n + 1 > "if you care cleared till this, it won't be hard for you to solve further"
U100 = 3(100) + 1
U100 = 301

 

[OakMoon!]

Yar luking at it and finding the formula will make it difficult.. take
5,9,13,17,21...... the difference between each value is 4.. make a formula... the difference is always the coefficient of n... so 4n+x.... find x by taking 1 value... ex 2nd term is 9... so 4*2+x=9... x=1 so formula is 4n+1
to find formulas with enequal difference we get a quadratic formula......2,5,10, 17, 26... difference between each value is as followed... 3,5,7,9.. now find the difference between this new sequence i.e. 2... divide this difference by 2 u ll get 1, this value is the cofficient of n2... make an equation... n2+an+b..... put in values frm the original eq and solve simultaneously to find a b......
THIS may be a long prcedure but its best to check ur answers and clear confusions... and when u get a 3 mark q on find the nth term.. then this is how u can easily do it without the trial and error method....

 

[Zishi]

you can also look at this one,
Un = an + b

where,
U= Unknown term
n= Position in sequence
a= Common Difference
b= Constant

for example,
Q: Calculate U100 of the following sequence,
4,7,10,13,16

Solution:
Un = an + b
U100 = 3n + 1 > "if you care cleared till this, it won't be hard for you to solve further"
U100 = 3(100) + 1
U100 = 301

LOL. You got that from the BBC activity, which I linked to another guy at this forum. Anyways, its good for you, too!

 

[emkay]

LOL. You got that from the BBC activity, which I linked to another guy at this forum. Anyways, its good for you, too!

yeah, it was way too easy! XD