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Solve for the value of x:cos 60 degrees +cos^2 60 degrees + cos^3 60 degrees +...+ =x
- Thread starter Jade-j
- Start date
D
Deleted member 4993
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Solve for the value of x:cos 60 degrees +cos^2 60 degrees + cos^3 60 degrees +...+ =x
The answer is 1 but how is it done?/ what is the solution?
Do you see that the left-hand-side is a geometric series?
Yes, I know it is a geometric series but it doesn't mean that the answer is always equal to 1. Right?
This is correct. There's absolutely no expectation that a generic geometric series will sum to 1. This specific series, however, does. You seem to be at least a little bit familiar with the concept of a geometric series, so do you know the closed form of the sum of a geometric series? (A refresher, if neededhttp://www.purplemath.com/modules/series5.htm) What is the first term of the series? What is the common ratio of the series? What does that make the sum of the series?