Respuesta :
Step-by-step explanation:
sin²x-1/cosx= -1
cosx=-(sin²x-1)
cosx=1-sin²x
cosx=cos²x
cosx=1
so option C is the correct answer
Step-by-step explanation:
sin²x-1/cosx= -1
cosx=-(sin²x-1)
cosx=1-sin²x
cosx=cos²x
cosx=1
so option C is the correct answer