What's wrong with my solution to this trigo question?

• Mikethm

  17 Jul 09, 01:53

  

  Hope either wee_ws or eagle or some kind soul can help me with the above question's solution. I took it from a 2008 prelim paper which took it from a 80s GCE O AM exams.

  I just can't agree with the given solution (in box) and I explained my rationale below it.

  My solution is the opposite of the answer sheet's.

  As I doubt the setter can set a question and give the wrong answer, therefore my answer must be wrong. But I can't figure out why...

  So I would appreciate if anyone can point out the flaw in my solution. Thanks.

• Lee012lee

  17 Jul 09, 04:33

   

  Hi Mikethm,

  The answer sheet's answer is wrong.

  Your answer is correct.

  The TYS's answer for this question which is June 1995 GCE "O" level Paper 2 Q5(b) question is the same as your answer.

  There is a similar question in Pan Pacific Additional Mathematics Textbook Page 300 Question 20(c). The answer is also the same as your answer.

   

• Mikethm

  20 Jul 09, 23:55

  Guess I have to assume the answer sheet had a typo.

  Thanks.