Q. The following geometric series has a sum to infinity as shown:16logx64+8logx64+4logx64+…=364.Calculate the value of x.
Identify Terms and Ratio: Identify the first term (a) and the common ratio (r) of the geometric series.The first term is 16logx64, and each subsequent term is half the previous term, which means the common ratio r is 21.
Use Sum Formula: Use the formula for the sum to infinity of a geometric series, which is S∞=1−ra, where S∞ is the sum to infinity.Given that S∞=364, we can set up the equation 364=1−2116logx64.
Solve for First Term: Solve for the first term a by simplifying the denominator of the right side of the equation.Since 1−21=21, the equation becomes 364=2116logx64.
Multiply and Calculate: Multiply both sides of the equation by 21 to isolate the first term a.This gives us 16logx64=364×21.
Divide and Solve Log: Calculate the right side of the equation.364×21=664=332.So, 16logx64=332.
Convert to Exponential: Divide both sides of the equation by 16 to solve for logx64.logx64=332×161.
Recognize and Rewrite: Calculate the right side of the equation.332×161=4832=32.So, logx64=32.
Simplify Exponent: Convert the logarithmic equation to its exponential form.x32=64.
Raise to Power: Recognize that 64 is 26, so the equation becomes x32=26.
Calculate Value: Since x is x21, rewrite the equation as x21⋅32=26.
Calculate Value: Since x is x21, rewrite the equation as x21⋅32=26.Simplify the exponent on the left side of the equation.21⋅32=31, so the equation becomes x31=26.
Calculate Value: Since x is x21, rewrite the equation as x21⋅32=26.Simplify the exponent on the left side of the equation.21⋅32=31, so the equation becomes x31=26.Raise both sides of the equation to the power of 3 to solve for x.x=(26)3.
Calculate Value: Since x is x21, rewrite the equation as x21⋅32=26.Simplify the exponent on the left side of the equation.21⋅32=31, so the equation becomes x31=26.Raise both sides of the equation to the power of 3 to solve for x.x=(26)3.Calculate the value of x.x=218.
Calculate Value: Since x is x21, rewrite the equation as x21⋅32=26.Simplify the exponent on the left side of the equation.21⋅32=31, so the equation becomes x31=26.Raise both sides of the equation to the power of 3 to solve for x.x=(26)3.Calculate the value of x.x=218.Recognize that 218 is a large number, but it is the correct value for x in this context.
More problems from Sum of finite series not start from 1