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Question

Mathematics Question on Differential equations

If an=24n216n+15a_n=\frac{-2}{4 n^2-16 n+15}, then a1+a2++a25a_1+a_2+\ldots \ldots+a_{25} is equal to:

A

52147\frac{52}{147}

B

50141\frac{50}{141}

C

51144\frac{51}{144}

D

49138\frac{49}{138}

Answer

50141\frac{50}{141}

Explanation

Solution

If an​=4n2−16n+15−2​ then a1​+a2​+………a25​
⇒n=1∑25​an​=∑4n2−16n+15−2​
=∑4n2−6n−10n+15−2​
=∑2n(2n−3)−5(2n−3)−2​
=∑(2n−3)(2n−5)−2​
=∑2n−31​−2n−51​
=471​−(−3)1​
=14150​