Math, asked by tenthy, 1 year ago

divide 32 into four parts which are in AP such that the product of extreames to the product of means is 7:15
can we use formula
Sn=n/2[2a+(n-1)d] to find d

Answers

Answered by amrit614
2
can you give me photo of the question

tenthy: shall i repost it
Answered by harpreet2497
0
Let the our parts are a-3d,a-d,a+d and a+3d.
Then by the given question,
a-3d+a-d+a+d+a+3d=32
or, 4a=32
or, a=8 and
(a-3d)(a+3d)/(a-d)(a+d)=7/15
or, a²-9d²/a²-d²=7/15
or, 15a²-135d²=7a²-7d²
or, 15a²-7a²=-7d²+135d²
or, 8a²=128d²
or, 8×8²=128d²
or, d²=8×8×8/128
or, d²=4
or, d=+-2
∴, The four parts are:
when d=2
8-(3×2)=8-6=2
8-2=6
8+2=10
8+(3×2)=14
when d=-2
8-(3×-2)=8+6=14
8-(-2)=8+2=10
8+(-2)=8-2=6
8+(3×-2)=8-6=2

tenthy: i said can we solve it by using formula of Sn
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