## Sequences IB Maths HL

Discussions for the Core part of the syllabus. Algebra, Functions and equations, Circular functions and trigonometry, Vectors, Statistics and probability, Calculus. IB Maths HL Revision Notes

### Sequences IB Maths HL

IB Mathematics HL – Arithmetic Sequence

An artist is creating a triangular shaped sculpture made of marbles.
There are 60 of the marbles in the first row with three less in each row. How
many marbles are in the 16th row?

Thanks
Max

Posts: 0
Joined: Mon Jan 28, 2013 8:06 pm

### Re: Sequences IB Math HL

IB Mathematics HL – Arithmetic Sequences (Progressions)

This situation is represented by an arithmetic sequence. Since the number of
marbles decreases by 3, the common difference is -3 and d = -3.
The first term is 60, common difference is d = -3, and n =16.
To find the nth term, you will use the following formula for a
arithmetic sequence:

$u_{n}=a+(n-1)d$
where $a=60, d=-3, n=16$
So
$u_{16}=60+(16-1)(-3)=60-45=15 marbles$

Hope these help!!
miranda

Posts: 268
Joined: Mon Jan 28, 2013 8:03 pm

### Re: Sequences IB Maths HL

Thanks miranda!!
Max

Posts: 0
Joined: Mon Jan 28, 2013 8:06 pm