Q. Find the 72nd term of the arithmetic sequence −23,−39,−55,…Answer:
Arithmetic Sequence Formula: To find the 72nd term of an arithmetic sequence, we need to use the formula for the nth term of an arithmetic sequence, which is:an=a1+(n−1)dwhere an is the nth term, a1 is the first term, n is the term number, and d is the common difference between the terms.
Identify First Term: First, we identify the first term a1 of the sequence, which is given as −23.
Find Common Difference: Next, we need to find the common difference d. We can do this by subtracting the first term from the second term:d=−39−(−23)=−39+23=−16
Calculate 72nd Term: Now that we have the first term and the common difference, we can find the 72nd term a72 using the formula:a72=a1+(72−1)d
Substitute Values: Substitute the known values into the formula:a72=−23+(72−1)(−16)a72=−23+(71)(−16)
Perform Calculation: Now, perform the multiplication and addition to find a72:a72=−23+(−1136)a72=−1159