Question

find the sum of the following A.p's :- -37,-33,-29,.........to 12 terms ?

Answer 1

Sum of AP=S(n)=n/2 [2a+(n-1)d].............(Sum of AP formula)...(1)

a=- 37 (1st term of the AP series)
d= 2nd term-1st term
  = -33 - (-37)  = -33+ 37
  =4
n=12 (no of terms)

Putting the values of n ,a and d in the above formula....(1)

Sum of 12 terms=12/2 [(2 × -37)+(12-1)×4]
                          =6[-74+44]
                          =6× -30
                          = -180

Answer 2

Answer:

Step-by-step explaination: Sum of AP=S(n)=n/2 [2a+(n-1)d].............(Sum of AP formula)...(1)

a=- 37 (1st term of the AP series)

d= 2nd term-1st term

 = -33 - (-37)  = -33+ 37

 =4

n=12 (no of terms)

Putting the values of n ,a and d in the above formula....(1)

Sum of 12 terms=12/2 [(2 × -37)+(12-1)×4]

                         =6[-74+44]

                         =6× -30

                         = -180