Question

Find The sum of the arithmetic sequences


-10 ¼ , -10 ½ , -10 ¾ ………. -25 ½​

Answer 1

Step-by-step explanation:

d=-1/4

a=-10 1/4 or -41/4

an = -102/4

an = a+(n-1)d

-102/4=-41/4 + (n-1)-1/4

-61/4 * -4 = n-1

61= n-1

62 = n

Sn = n/2(a+an)

Sn = 62/2(-41/4 + -102/4)

Sn = 31(-143/4)

Sn = -4433/4 = -1108.25