Find the first four terms of this geometric sequence. a1=40 and r=0.5

In a geometric sequence, u find the next term by multiplying by the common ratio (r), which in this problem = 0.5

A1means first term

so the first term is 40
second term would be 40 * 0.5 = 20
third term is 20 * 0.5 = 10
fourth term is 10 * 0.5 = 5

so ur first 4 terms are : 40, 20, 10, 5

Exponential function