Grade 11TrigonometryThe no.of solytions of tan x + sec x= 2 cos xin [0 ,2π] NARENDRA YADAV 8 Years agoGrade 11
Arun8 Years agoDear Narendra, tanx+sec x=2cosx => sin x/cos x + 1/cosx=2 cosx =>(sinx+1)/cosx = 2cosx => 1+sinx=2 cos^2 x=>1+sin x=2(1-sin^2 x) =>1+sinx -2(1+sinx)(1-sinx)=0 => (1+sinx)(1-2(1-sinx))=0 =>(1+sinx)(2sinx-1)=0so sin x=1, sin x=1/2so in between [0,2pi], the solutions are x=3pi/2, x=pi/6, x=5pi/6.therefore there are 3 solutions. Cheers!!Regards,Arun (askIITians forum expert)