Question

If you are a genius then answer this...
Q. The sum of first n terms of a sequence is 4n^2 - 5n show that the series is an A.P. Also find the 60th term.​

Answer 1

Step-by-step explanation:

x1= 4×1^2-5×1

= 16-5

= 11

x2= 4×2^2-5×2

= 64-10

= 54

x3=4×3^2-5×3

= 144-15

= 129

d= x2-x1

= 54-11

= 43

d= x3-x2

= 129-54

=75

common difference,d is not same.

therefore it is not an ap.

x60= 4×60^2-5×60

= 57600-300

= 57300