Question

if sn=4n-n square,then a10= ??​

Answer 1

see attachment

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Answer 2

Step-by-step explanation:

Given: Sn= 4n-n

then,

taking n = 1

S1 = 4×1-1²

= 4 - 1

= 3

So, Sum of first term of Ap is 3

Finding 2nd term

Sum of first two term is 4

first term + second term = 4

3 + A2 = 4

A2 = 1

Hence In AP ,

first term = 3

Common difference(d) = 2nd term - 1st term

1 - 3 = -2

Now, We need to find 10th term,

A10 = a + ( 10 - 1) d

= 3 + 9 × (-2)

= -15___Answer

hope it's help you ✌ ❤