Given: sec0=1, secX=1/cosX
we hv to find cos0,
We Have given:
SecX = 1/cosX
multiply cosX both side to get
secX × cos X =cosX /cos X
i.e, secX × cosX = 1
Relace X by '0', coz we hv to find for this angle
so equation becomes
sec0 × cos 0 = 1
given sec 0 = 1
i.e, 1 × cos 0 = 1
i.e, cos 0 = 1
✌️:)