Question

nth term of an ap is given by an=5-6n.find the sum of first n terms of the ap​

Answer 1

Answer: the nth term of an AP is given by an=5-6n

so, a1= 5-6(1)= -1

a2=5-6(2)= -7

a3=5-6(3)= -13

so a= -1 and d= -6

now, sn=$\frac{n}{2}( 2a+(n-1)d)$

=$\frac{n}{2}$(-2-6n+6)

=$\frac{n}{2}$(4-6n)

so, here is your answer hope it helps you