Find the sum of the first 18 odd positive integers.
Accepted Solution
A:
Answer:The sum of the first 18 odd positive integers is 324.Step-by-step explanation:Given : The first 18 odd positive integers.To find : The sum of the first 18 odd positive integers?Solution : The odd positive integers are 1,3,5,.... forming an Arithmetic sequence .Where, First term is a=1Common difference is d=2Number of terms n=18The sum of A.P formula is [tex]S_n=\frac{n}{2}[2a+(n-1)d][/tex]Substitute the values in the formula,[tex]S_{18}=\frac{18}{2}[2(1)+(18-1)2][/tex][tex]S_{18}=9[2+(17)2][/tex][tex]S_{18}=9[2+34][/tex][tex]S_{18}=9[36][/tex][tex]S_{18}=324[/tex]Therefore, The sum of the first 18 odd positive integers is 324.