Find the sum of the infinite series tan2 θ − tan4 θ + tan6 θ + . . + (−1)n−1 tan2n θ + . . whenever the series converges.

The line plot below represents the number of letters written to overseas pen pals by the students at the waverly middle school.each x represents 10 students. how many students wrote more than 6 and fewer than 20 letters. a.250 b.240 c.230 d.220