Login

Search the forums now!

Welcome, Guest. Please login or register.

April 27, 2024, 10:52:01 pm
Pages: [1]   Go Down

Author Topic: Trigonometry  (Read 594 times)  Share 

0 Members and 1 Guest are viewing this topic.

terassy

  • Trailblazer
  • *
  • Posts: 31
  • Respect: 0
Trigonometry
« on: June 13, 2018, 08:01:36 pm »
0
Someone pls help me with this question:

Simply the following in terms of the indicated angle:
2cos22A - 1; 4A
Logged

RuiAce

  • ATAR Notes Lecturer
  • Honorary Moderator
  • Great Wonder of ATAR Notes
  • *******
  • Posts: 8814
  • "All models are wrong, but some are useful."
  • Respect: +2575
Re: Trigonometry
« Reply #1 on: June 13, 2018, 08:19:53 pm »
+3
This is just \( \cos 4A\) using the double angle identity \( \cos 2\theta = 2\cos^2\theta - 1\) (in which we make the substitution \( \theta = 2A \)).
Logged
Pages: [1]   Go Up