Consider an infinite geometric series with first term a and common ratio r . If its sum is 4 and the second term is 4 3 , then:

Question

Consider an infinite geometric series with first term a and common ratio r . If its sum is 4 and the second term is 4 3 ​ , then:

TestHub · Accepted Answer

Since, sum = 4 and second term = 4 3 ​ ⇒ 1 − r a ​ = 4 , and a r = 4 3 ​ ⇒ 1 − 4 a 3 ​ a ​ = 4 ⇒ ( a − 1 ) ( a − 3 ) = 0 ⇒ a = 1 or a = 3 ⇒ 1 − 4 a 3 ​ a ​ = 4 ⇒ ( a − 1 ) ( a − 3 ) = 0 ⇒ a = 1 or a = 3 ​

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