Consider the equation 2cos^2x + sinx - 1 = 0
a) Explain why the equation cannot be factored.
b) Suggest a trigonometric identity that can be used to remove the problem identified in part a).
c) Apply the identity and rearrange the equation into a factorable form.
d) Factor the equation.
e) Determine all solutions in the interval x E [0,2pi].
Ok.. so I tried to factor it. This is my steps:
2cos^2x + sinx - 1 =0
Err i change the way it looks to make it easier for me
2x^2 + x - 1 =0
2x^2 + 2x -1x -1
(2x^2 + 2x) + (-1x - 1)
2x(x+1) -1(x+1)
(2x-1)(x+1)
(2cosx - 1)(cosx + 1)
Isn't that factoring it? Why is it asking why you
cannot factor it? What am I doing wrong?
