Question

for what value of nth term of two AP's 59,61,63------ and -11,-4,3,10 are equal

please very urgent

Answer 1

heya,its too easy.

in your first Given Ap

a=59,
d=61-59

d=2

,so,tn=a+(n-1)d

tn=59+2n-2

tn=57+2n_____1)

,and again in second Ap.

a=-11 ,d=-4-(-11)=)d=7

tn=-11+7n-7

tn=7n-18__:::2

according to question both are equal to each other.

so,57+2n=7n-18

5n=75
n=15.

nth term is 15 where both's value are equal.

hope it help you.


@rajukumar☺

Answer 2

59,61,63.....
A= 59
D= 2
an= a + (n-1)d
an=59+(n-1)2
an=59+2n-2
an=57+2n ...... (EQ 1)
-11,-4,3,10......
A = -11
D = 7
an= a +(n-1)d
an= -11+(n-1)7
an= -11+7n-7
an=-18+7n ..... (EQ 2)
EQ 1=EQ 2
57+2n=-18+7n
57+18=7n-2n
75=5n
n=15