Question

using ap find sum of all even integers between 6 and 431

Answer 1

Answer:

46434

Step-by-step explanation:

a1=6

d = 2

an = 430 (greatest even no. in the AP)

an =  a + (n-1) d

430 = 6 + (n-1)2

n-1 = 212

n = 213

S213 = n/2( a1 + an)

        = 213/2 (6+430)

        = 213 x 218

        = 46434

           =====

Answer 2

6,7,8,.............431

here a=6. d=1. and tn=431

tn=a+(n-1) d

431=6+(n-1) 1

431-6=n-1

425=n-1

426=n

n=426

Sn=n/2(2a+(n-1)d

S426=426/2[2×6+(426-1)1]

S426=213[12+(425)1]

= 213[12+ 425 ]

= 213×437

= 93081

the sum of all integers between 6 and 431 is 93081