# What does this notation (unmatched right parenthesis after a summation) mean?

My textbook contains this notation:

$$\sum_{n=0}^{\infty} r^{2n}\cos n\theta \bigg) ^2 + \quad \sum_{n=0}^{\infty} r^{2n} \sin n\theta \bigg) ^2$$

What does this notation mean? Square the result of the summation? Square each term of the summation?

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What textbook are you using? –  Clayton Feb 5 '13 at 3:23
@Clayton: The textbook is "Mathematical Methods in the Physical Sciences" by Mary L. Boas, Third Edition. I'm looking for errata now. –  Matthew Pirocchi Feb 5 '13 at 3:27
@Clayton: See my comment on DoctorBatmanGod's answer--it was a typographical error. –  Matthew Pirocchi Feb 5 '13 at 3:29
Glad it was cleared up! –  Clayton Feb 5 '13 at 3:31

The only time I can think of where unmatched parentheses are used is in defining half open intervals, e.g. $$(a,b] \text{ or } [a,b)$$