Okay so I know how to do these (sorta, I was off in the lesson and I've caught up but I'm still not entirely sure!) A question they did in the lesson was:
1) The sequence u1 u2 u3 is defined by the recurrence relation
where d is constant u1=2
a)Show that U5=2
b)Deduce an expression for u10 in terms of d
c) Given that U3=3U2, find the value of d
I have a lesson tomorrow so I could really do with getting this answered as soon as possible!
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C1 Sequences and Series Question NEED HELP watch
- Thread Starter
- 30-10-2016 16:37
- Official Rep
- 01-11-2016 17:50
Sorry you've not had any responses about this. Are you sure you've posted in the right place? Here's a link to our subject forum which should help get you more responses if you post there.
Just quoting in Fox Corner so she can move the thread if needed
Spoiler:Show(Original post by Fox Corner)
- 02-11-2016 10:50
For part a you have to go through the sequence. U2=(-1)^2U1+d=d+2
U3= (-1)^3[d+2]+d=-2 etc etc and U5 turns out to be 2 because of the way that all the ds cancel.
By looking at the pattern of ds and 2 in the terms you have found you can deduce what U10 is.
for part c you have U3 and U2 from part a and so can set up the equ and solve for d