three numbers of ap are a,a+d,a+2d there sum is 24 and the sum of the squares is 224. find the term
Answers
Answer:
let the terms be a-d, a, a+d
sum=24
a-d+a+a+d=3a=24
a=8
(a-d) ^2+a^2+(a+d)^2=224
a^2+2(a^2+d^2)=224
3a^2+2d^2=224
3(64)+2d^2=224
2d^2=224-192
d^2=32/2
d=√16=4 put in numbers(assumed )
check calculation.. procedure will b same..
Step-by-step explanation:
Since the numbers are in A.P , they have a common difference 'd' and term 'a'. Also, we have to assume the three numbers to be (a-d), (a), and (a+d) to find out one of the two unknown variables, i.e, a or d
A.T.Q ,
(a-d) (a)+ (a+d) = 24
=》 a -d + a+ a+d = 24
=》 3a + d-d = 24
=》 3a = 24
=》a= 24/3
=》a= 8 ------ eq 1
Also A.T.Q ,
(a-d)^2 + (a)^2 + (a+d)^2 = 224
=》 a^2 -2ad +d^2 + a^2 + a^2 + 2ad +d^2 = 224 { using the formula (a+b)^2 }
=》3a^2 - 2ad + 2ad + d^2 +d^2 = 224
=》3a2 +2d^2 = 224
=》3x8x8 + 2d^2 = 224 ( putting the value of a from eq 1)
=》192 + 2d^2 = 224
=》 2d^2= 224 -192
=》2d^2 = 32
=》d^2 = 16 ( dividing by 2)
=》\/d = \/16 (putting root)
=》 d=4.--------- eq 2
now, we assumed 1st number to be (a-d)
putting the values of a and d, we get = 8-4 = 4
2nd number = a = 8
3rd number =(a+d) = 8+4 =12.
Therefore, the required numbers are 4 , 8 , 12.