Find the exact value of tan 7pi/6

Proceed as in example 3 in section 6.1 to rewrite the given expression using a single power series whose general term involves xk. ∞ n(n − 1)cnxn − 2 n = 2 − 4 ∞ ncnxn n = 1 + ∞ cnxn n = 0

The pyramid below was dissected by a horizontal plane which shape describes the pyramid horizontal cross section

Which radical expression is a rational number? a. √ 360 b. √ 644 c. √ 225 d. √ 122