if the sum of the 1st n term of an A.P given by Sn=4n2-3n,find the 1st term and the common difference.also write the 1st three terms.
Answers
Answered by
0
sn = 4n²-3n
s1 = 4*1²-3*1= 4-3=1
s2= 4*2²-3*2 =16-6=10
s3= 4*3²-3*3=36-9=27
s4= 4*4²-3*4=64-12=52
first term = a1 = s2-s1 =10-1=9
a2 = s3-s2=27-10 =17
a3=s4-s3 =52-27=25
common difference =d = a2-a1 =17-9 =8
s1 = 4*1²-3*1= 4-3=1
s2= 4*2²-3*2 =16-6=10
s3= 4*3²-3*3=36-9=27
s4= 4*4²-3*4=64-12=52
first term = a1 = s2-s1 =10-1=9
a2 = s3-s2=27-10 =17
a3=s4-s3 =52-27=25
common difference =d = a2-a1 =17-9 =8
Similar questions