Bryn Posted March 21, 2004 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.
Dave Posted March 21, 2004 Posted March 21, 2004 Try rewriting the equation using a = sin(x), b = cos(x) and factorising it.
wolfson Posted March 21, 2004 Posted March 21, 2004 Use the fact that 4sinxcosx-2sinx-2cosx+1 = (2sinx-1)(2cosx-1).
Neurocomp2003 Posted March 21, 2004 Posted March 21, 2004 used your sincos laws. Find them in your book -1
wolfson Posted March 21, 2004 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.
Bryn Posted March 21, 2004 Author Posted March 21, 2004 are that's it, so easier once i knew to factorise it, must remeber to look out for that. Thanks.
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