3sinx = 2cosx
let us square both sides:
==> 9sin^2 x = 4cos^2 x..........(1)
We kow that :
sin^2 x + cos^2 x = 1
==> sin^2 x = 1 - cos^2 x
==> Substitute in (1):
==> 9(1-cos^2 x) = 4cos^2 x
==: 9 - 9cos^2 x = 4cos^2 x
Combine like terms:
==> 9- 13cos^2 x = 0
==> 13cos^2 x = 9
==: cos^2 x = 9/13
==> cosx = +-3/sqrt13
==> x= arccos(3/sqrt13) + 2npi
We’ll help your grades soar
Start your 48-hour free trial and unlock all the summaries, Q&A, and analyses you need to get better grades now.
- 30,000+ book summaries
- 20% study tools discount
- Ad-free content
- PDF downloads
- 300,000+ answers
- 5-star customer support
Already a member? Log in here.
Are you a teacher? Sign up now