49,812 views
45 votes
45 votes

cosx -1 =sin^(2)x solution

cosx -1 =sin^(2)x solution-example-1
User Justin Soliz
by
2.8k points

1 Answer

14 votes
14 votes

Answer:

x = 0°, 360°

Explanation:

  • Formula : cos²x + sin²x = 1
  • so sin²x = 1 - cos²x

using the formula:

cosx - 1 = 1 - cos²x

cos²x +cosx - 1 - 1 = 0

cos²x +cosx - 2 = 0

cos²x + 2cosx - cosx -2 = 0

cosx ( cosx + 2 ) -1 ( cosx + 2 ) = 0

(cosx - 1) (cosx + 2 ) = 0

cosx = 1 , cosx = -2


x = cos^(-1) ( 1 ) ,
x = cos^(-1) ( -2 )

x = 0° , 360° , Not applicable

User Paul Turchenko
by
3.0k points