I need a little help on this one

kaebun

Junior Member
Joined
Sep 11, 2005
Messages
135
solve all solutions from [0,2pi)
sin2x=sinx so i did
2sinxcosx=sinx
i don't know what else to do... am just not imaginitive or what? i just can't think of anything that will work
 
Your imagination is just fine, Kaebun.

Now you can move the sin(x) to the LHS, factorise, and solve just as we normally would.
 
so ...
sinx(2cosx-1)=0
sinx=0
2cosx-1=o
cosx=1/2

so.. x=o, pi, pi/3, & 5pi/3

is that right? thank you for your help!
 
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