Bryn Posted March 21, 2004 Share Posted March 21, 2004 4sinxcosx-2sinx-2cosx+1 = 0 Need all solutions in the range 0 < x <=360 Just a clue would be nice, i'm totally flummaxed. question 22 of excercise 2c in the edexcel p1 book if you have it. Link to comment Share on other sites More sharing options...
Dave Posted March 21, 2004 Share Posted March 21, 2004 Try rewriting the equation using a = sin(x), b = cos(x) and factorising it. Link to comment Share on other sites More sharing options...
wolfson Posted March 21, 2004 Share Posted March 21, 2004 Use the fact that 4sinxcosx-2sinx-2cosx+1 = (2sinx-1)(2cosx-1). Link to comment Share on other sites More sharing options...
Neurocomp2003 Posted March 21, 2004 Share Posted March 21, 2004 used your sincos laws. Find them in your book -1 Link to comment Share on other sites More sharing options...
wolfson Posted March 21, 2004 Share Posted March 21, 2004 ^^is fine Link to comment Share on other sites More sharing options...
wolfson Posted March 21, 2004 Share Posted March 21, 2004 Well, the equation becomes (2sinx-1)(2cosx-1)=0. This equation is satisfied if 2sinx-1=0 or 2cosx-1=0. So, the values for x are found by solving these two equations. Link to comment Share on other sites More sharing options...
Bryn Posted March 21, 2004 Author Share Posted March 21, 2004 are that's it, so easier once i knew to factorise it, must remeber to look out for that. Thanks. Link to comment Share on other sites More sharing options...
wolfson Posted March 22, 2004 Share Posted March 22, 2004 No problem any time just ask Link to comment Share on other sites More sharing options...
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