[Add. Maths] Trigo

• tr@nsp0rt_F3V3R

  22 Mar 09, 21:11

  This is a test paper from NorthBrooks Sec: MYE 2008

  Proof:

   

   

   

• tr@nsp0rt_F3V3R

  22 Mar 09, 21:12

  I'm completely stucked, and i see no link... ...

  so if possible, help in pls ^^

  thx

• wee_ws

  22 Mar 09, 21:45

  Hi,

    Start with LHS and use the fact that cos (A + B) = cos A cos B - sin A sin B.

    Since, we want the denominator to become tan B, we divide numerator and denominator by cos A cos B.

    Try it, thanks!

  Cheers,
  Wen Shih

• tr@nsp0rt_F3V3R

  22 Mar 09, 22:21

  Originally posted by wee_ws:

  Hi,

    Start with LHS and use the fact that cos (A + B) = cos A cos B - sin A sin B.

    Since, we want the denominator to become tan B, we divide numerator and denominator by cos A cos B.

    Try it, thanks!

  Cheers,
  Wen Shih

  Hi,

  thx for helping

  but...... 
  Since, we want the denominator to become tan B, we divide numerator and denominator by cos A cos B.

  dis step... kinda elabrate on it pls...

  i do the both sides techqunie, and results:

   

• eagle

  22 Mar 09, 22:43

  err

  As Mr. Wee has said, use cos (A + B) = cos A cos B - sin A sin B

  So,

  cos (A + B) / cos A sin B = (cos A cos B - sin A sin B) / cos A sin B

  To get denominator equal to tan B, divide top and bottom by cos A cos B

  Then u get answer already.

   

• tr@nsp0rt_F3V3R

  22 Mar 09, 23:49

  kk get it... thx a lot all ^_^