中4數學2題

1.tan x+2 cot x = 3
tan x + 2/tan x = 3
(tan x)^2 + 2 = 3 tanx
(tan x)^2 - 3tanx + 2 = 0
(tanx -1)(tanx - 2) = 0
tanx = 1 or 2
x = 45, 225, 63.43, 243.43 (2 d.p.)
2.2sec^2 x = 5 tan x
2(1+(tanx)^2) = 5tan x
2(tanx)^2 - 5 tan x + 2 = 0
(2tanx - 1)(tanx - 2) = 0
tanx = 1/2 or 2
x = 26.57, 206.57, 63.43, 243.43 (2 d.p.)