For the following sequence determine the common difference (if it is an arithmetic sequence) or the common ratio (if it is a geometric sequence).205,40,165,…25525555
Q. For the following sequence determine the common difference (if it is an arithmetic sequence) or the common ratio (if it is a geometric sequence).205,40,165,…25525555
Identify Sequence Type: First, let's identify if the sequence is arithmetic or geometric by examining the relationship between consecutive terms.
Calculate First Term Difference: To determine if it's an arithmetic sequence, we subtract the second term from the first term: 40−205
Calculate Second Term Difference: Now, let's calculate the difference using the value of 5 which is approximately 2.236:40−20(2.236)=40−44.72=−4.72This does not seem to be a consistent difference, but let's check the next pair of terms to be sure.
Check Arithmetic Sequence: Subtract the third term from the second term: 165−40
Check Geometric Sequence: Calculate the difference using the value of 5:16(2.236)−40=35.776−40=−4.224 The differences between terms are not consistent, so this is not an arithmetic sequence.
Divide Second by First Term: Now let's check if it's a geometric sequence by dividing the second term by the first term: 20540
Calculate Ratio Simplification: Simplify the division: 40/(205)=2/5
Divide Third by Second Term: Next, divide the third term by the second term to see if the ratio is consistent: 40165
Compare Ratios: Simplify the division:(165)/40=(16/40)×5=0.4×5
Determine Sequence Type: Now, let's compare the ratios: 52 and 0.4×5To see if they are the same, we can multiply the second ratio by 55 to rationalize the denominator:(0.4×5)×(55)=0.4×5=2
Determine Sequence Type: Now, let's compare the ratios: 52 and 0.4×5To see if they are the same, we can multiply the second ratio by 55 to rationalize the denominator:(0.4×5)×(55)=0.4×5=2Since both ratios are equal to 2, we have determined that the sequence is a geometric sequence with a common ratio of 2.