The 8th term of an AP is 37 and 12th term is 57. Find the AP.
Answers
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GIVEN :
The 8th term of an AP is 37 .
The 12th term of an AP is 57.
TO FIND :
The AP
ANSWER :
The general term,tn =
where n is the nth term.
a is the first term.
d is the common difference.
t8 = a + ( 8 - 1) d
a + 7d = 37 ________(1)
t12 = a + (12 - 1) d
a + 11d = 57 _________(2)
Subtract (1) & (2) ,
(2) => a + 11d = 57
(1) => a + 7d = 37
(-) (-) (-)
_________________
4d = 20
d = 20/4
d = 5 .
Substitute the value of d = 5 in equation (1),,,,
(1) => a + 7 (5) = 37
a + 35 = 37
a = 37 - 35
a = 2
The general form of an AP is ,,,,,
AP = 2 ,( 2 + 5) , ( 2 + 2 ×5) , ....
AP = 2 , 7, 12,....
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