question of 10 class's maths
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Let a be the first term and d be the common difference of given AP.
Now, According to the question,
a8=1/2(a2) & a11=1/3(a4)+1
⇒2×(a+7d)=a+d⇒a+13d=0 ...(1)
and 3×(a+10d)=(a+3d)+3⇒2a+27d=3 ...(2)
On applying (2)−2×(1), we get
d=3
Putting d=3 in (1), we get
a+13×3=0⇒a=−39
Now, a
15
=a+14d=−39+14×3=3
∴a15=3
Step-by-step explanation:
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Answered by
0
Let a be the first term and d be the common difference of given AP.
Now, According to the question,
a8=1/2(a2) & a11=1/3(a4)+1
⇒2×(a+7d)=a+d⇒a+13d=0 ...(1)
and 3×(a+10d)=(a+3d)+3⇒2a+27d=3 ...(2)
On applying (2)−2×(1), we get
d=3
Putting d=3 in (1), we get
a+13×3=0⇒a=−39
Now, a
15
=a+14d=−39+14×3=3
∴a15=3
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