Definition of a geometric series:
The Attempt at a Solution
Basically I can use the geometric series idea and implement it into the denominator of the question (i.e. sub x=2 into the equation from part b and change the lower index to n=1)
Taking the derivate of both sides:
Multiplying both sides by 2:
Of course I can simplify the question furthermore and get a single value as a result, my problem is I don't understand on how to incorporate the numerator (sin n) into the problem. Is my approach correct, or am I substituting the wrong x-value?
Thanks in advance for any help/advice. :)