∵ b = √（a ² - 1）+ √（1 - a ²）+ 6∴ a ² - 1 ≥ 01 - a ² ≥ 0∴ a ² - 1 = 0a ² = 1a = ± 1① 当 a = 1 时,则 b = √0 + √0 + 6 = 6② 当 a = - 1 时,则 b = √0 + √0 + 6...