In a geometric sequence, the first term, a1, is equal to 1 , and the third term, a3, is equal to 36 . Which number represents the common ratio of the geometric sequence?r=3r=4r=5r=6
Q. In a geometric sequence, the first term, a1, is equal to 1 , and the third term, a3, is equal to 36 . Which number represents the common ratio of the geometric sequence?r=3r=4r=5r=6
Identify Given Terms: Identify the given terms in the geometric sequence.We are given the first term a1 and the third term a3 of the geometric sequence. The first term is 1a1=1 and the third term is 36a3=36.
Write nth Term Formula: Write the formula for the nth term of a geometric sequence.The nth term of a geometric sequence is given by an=a1⋅r(n−1), where a1 is the first term and r is the common ratio.
Express Third Term: Use the formula to express the third term in terms of the first term and the common ratio.We have a3=a1⋅r3−1=a1⋅r2.
Substitute Given Values: Substitute the given values into the equation.We know that a1=1 and a3=36, so we can write 36=1×r2.
Solve for Common Ratio: Solve for the common ratio r. To find r, we take the square root of both sides of the equation: r2=36, so r=±36.
Determine Positive Ratio: Determine the positive value of the common ratio.Since a common ratio in a geometric sequence is typically positive, we take the positive square root of 36, which is 6. Therefore, r=6.
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