Question

2cos square theta - 11 coas theta +5 = 0

Answer 1

2cos^2X - 11 cosX +5 =0

2cos^2X -cosX- 10cosX +5 =0

cosX( 2cosX - 1) -5( 2 cosX -1)=0

(2cosX - 1) (cosX - 5 )=0

now,

2cosX -1 =0

2cosX=1

cosX=1/2

and ,

cosX- 5=0

coax = 5 ,which is not

possible .cause

the maximum

value of cosX is 1.

therefore, cosX = 1/2.