Solve finding all solutions in 0 2 pi 15 tan x sec x square
Solve, finding all solutions in [0, 2 pi). 15) tan x sec x = squareroot 2
Solution
15) tanx secx =2
(sinx/cosx)(1/cosx)=2
(sinx/cos2x)=2
sinx=cos2x2
sinx=(1-sin2x)2
sinx=2 -2sin2x
2sin2x +sinx=2
sin2x +(1/2)sinx=1
sin2x +(1/2)sinx +(1/22)2=1 +(1/22)2
(sinx +(1/22))2=(9/8)
(sinx +(1/22))=(-3/22),(sinx +(1/22))=(3/22)
(sinx )=(-4/22),(sinx )=(2/22)
sinx =(-2/2),(sinx )=(1/2)
sinx =-2,(sinx )=(1/2)
sinx =-2 => no solution ,
(sinx )=(1/2) => x =/4 ,3/4
therefore solution is x =/4 ,3/4
