Posted by **Sharon** on Sunday, April 20, 2008 at 11:03pm.

Find the solutions for sec^2x+secx=2 that fit into the interval [0, 2pi]

I figured out that pi/3 (after factoring and switching things around) was a solution, but then I got stuck on cos x = 1/3.

- Pre-Calculus -
**Reiny**, Monday, April 21, 2008 at 12:31am
no!

why don't you factor it with the secant as is

sec^2 x + secx - 2 = 0

(secx + 2)(secx-1) = 0

secx = -2 or secx = 1

cosx = -1/2 or cosx = 1

from cosx = -1/2, x = 120º (2pi/3) or 240º (4pi/3)

or

from cosx = 1, x = 0 or 360º (0 or 2pi)

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