Q. Find an explicit formula for the geometric sequence3, 15, 75, 375, ....... Note: the first term should be a(1).a(n)=
Calculate Common Ratio: We need to identify the common ratio r of the geometric sequence. To do this, we divide the second term by the first term.Calculation: r=315=5
Write Explicit Formula: Now that we have the common ratio, we can write the explicit formula for the nth term of a geometric sequence, which is a(n)=a(1)×r(n−1), where a(1) is the first term and r is the common ratio.
Plug in Values: We know the first term a(1) is 3 and the common ratio r is 5. Plugging these values into the formula gives us the explicit formula for the sequence.Calculation: a(n)=3×5(n−1)