Posted by anon on Monday, October 21, 2013 at 5:36pm.
cos2xsinx=0. Factor and solve for sinx

math  Reiny, Monday, October 21, 2013 at 5:43pm
1  2sin^2 x  sinx = 0
2sin^2 x + sinx  1 = 0
(2sinx  1)(sinx + 1) = 0
sinx = 1/2 or sinx = 1
in degrees, x = 30° , 150° , 270°
in radians, x = π/5 , 5π/6 , 3π/2

math  anon, Monday, October 21, 2013 at 5:46pm
Thanks. I was wondering, why is it "+ sin x" in the second step?

math  anon, Monday, October 21, 2013 at 5:47pm
do you just change all the signs of the terms? if so, why is this necessary?

math  Reiny, Monday, October 21, 2013 at 5:51pm
I multiplied each term by 1
(notice all the signs have switched)
I like my quadratics to start with a positive coefficient, although that would not be necessary.
It just makes it easier to factor.

math  anon, Monday, October 21, 2013 at 5:55pm
ok thank you.
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