00:02
In this question, the given data is common difference is given that is equal to d that is given 9, then total number of terms that is given n is equal to 18 and sum of n terms that is as an or i can say that as 18 is given that is equal to 1 ,521.
00:25
Now in the question it is saying that we have to find the value of missing term out of given 5 terms that is a1 comma n comma d comma a n so let's start answering this question so first we have to check that what what the missing terms are so what are the missing terms so here after looking the data i can say that d is given that means is given then n is given and s n is given so the missing terms are that is two missing terms that is first is a1 and second is a n so we have to find these two missing terms so let's start answering this question step by step so first i will try to find first missing term that is a 1 so by using the formula that is first formula is sum of n term of automatic sequence that is s n is equal to n over 2 multiplied by parentheses of a 1 plus a n now next step is substitute the data that is given in the question that is n is given that will be equal to 18 and is given that is 1 ,521 so after putting the step will be next step will be written as that is 1 ,521 is equal to 8 ,000 ,000.
02:19
18 over 2 will give that is 9 multiplied by parenthesis of a1 plus an.
02:26
Now again simplify 8 then i will get that is result will be that is a1 plus an is equal to 169.
02:46
So i can say that this is a step number 1.
02:51
Sorry this is equation number 1.
02:55
Now i am using another formula for finding the an missing term a, a and sorry a 1 so formula is that is n the term of arithmetic sequence will be written as that is a n is equal to a 1 plus parenthesis of n minus 1 multiplied by d so use this formula and substitute the data that is given in the cushion that is n is given that will be equal to 18 and d is given in the question that is 9 and a 1 which i get in above sorry so we have to only put these two data in above formula so it will be written as result will be that is a n is equal to a 1 plus n minus 1 that means 18 minus 1 that will give 17 multiplied by d that is 9 so simplify it then i will get a n is equal to a 1 plus 1 1 1 1 1 so this is a equation number 2.
04:21
So next step is put the value of a1 from equation number 2 in a step in equation number 1...