Originally Posted by
amanda0603
#1) 2sin^2X=sinX
$\displaystyle 2\sin^2{x} - \sin{x} = 0$
$\displaystyle \sin{x}(2\sin{x} - 1) = 0$
set each factor equal to 0 and solve for x
#2) cosX=sinX
solve this one by looking at your unit circle
#3) tanX+secX=1
$\displaystyle \sec{x} = 1 - \tan{x}$
square both sides ...
$\displaystyle \sec^2{x} = 1 - 2\tan{x} + \tan^2{x}$
$\displaystyle 1 + \tan^2{x} = 1 - 2\tan{x} + \tan^2{x}
$
$\displaystyle 0 = -2\tan{x}$
solve for x