Question

An=4, d=2, Sn=90,find n and a​

Answer 1

Answer:

okkk i can do it now

Step-by-step explanation:

sn=90,an= 4,d=2,and find n , a

formula =sn= n/2(2a+(n-1)d

according to formula

90=n/2[2a+(n-1)2]

90 = n/2(2a+2n -2)

90=n/2[2(a+n-1)]

90= n/2×2(a+n-1)

90=n(a+n-1). (2se 2 cut gaya kyuki n ke upon me 2 tha aur multiply me me bhi

2 )

90=an +n^ -1

90=4+n^-1

90=3 +n^

90/3=n^

30=n^

√30 = n

means of ^ square

I hope it is help Full for u