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hannahg
Group Title
Find all solutions in the interval [0, 2π).
sin2x + sin x = 0
 one year ago
 one year ago
hannahg Group Title
Find all solutions in the interval [0, 2π). sin2x + sin x = 0
 one year ago
 one year ago

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.Sam. Group TitleBest ResponseYou've already chosen the best response.2
Do you know what's the identity for sin2x?
 one year ago

hannahg Group TitleBest ResponseYou've already chosen the best response.0
noo i forgot..
 one year ago

.Sam. Group TitleBest ResponseYou've already chosen the best response.2
sin2x=2sinxcosx
 one year ago

.Sam. Group TitleBest ResponseYou've already chosen the best response.2
So how do you proceed?
 one year ago

hannahg Group TitleBest ResponseYou've already chosen the best response.0
2sinx+cosx+sinx=0 right? what do i do next?
 one year ago

.Sam. Group TitleBest ResponseYou've already chosen the best response.2
no, it should be from sin2x + sin x = 0 to 2sinxcosx + sin x =0 right?
 one year ago

.Sam. Group TitleBest ResponseYou've already chosen the best response.2
you should try factoring now
 one year ago

hannahg Group TitleBest ResponseYou've already chosen the best response.0
sinx(2cosx+1)=0 is this right? what do i do next? o.O
 one year ago

AravindG Group TitleBest ResponseYou've already chosen the best response.1
ya u r right :)
 one year ago

.Sam. Group TitleBest ResponseYou've already chosen the best response.2
yes, now you can let sinx=0 and 2cosx+1=0 then find the x values
 one year ago

AravindG Group TitleBest ResponseYou've already chosen the best response.1
equate that to 0 and find x values
 one year ago

hannahg Group TitleBest ResponseYou've already chosen the best response.0
so i got cosx=1/2 how do i find the value of x?
 one year ago

.Sam. Group TitleBest ResponseYou've already chosen the best response.2
well you can do this cosx=1/2 x=cos^{1} (1/2)
 one year ago

hannahg Group TitleBest ResponseYou've already chosen the best response.0
so what are all possible values of x? 0 and......what else O.o
 one year ago

AravindG Group TitleBest ResponseYou've already chosen the best response.1
@hannahg :) instead of o.O
 one year ago

.Sam. Group TitleBest ResponseYou've already chosen the best response.2
no its not 0
 one year ago

hannahg Group TitleBest ResponseYou've already chosen the best response.0
@AravindG :)
 one year ago

.Sam. Group TitleBest ResponseYou've already chosen the best response.2
you calculate cos^(1) 1/2 first without minus on half you'll get 60 degrees
 one year ago

.Sam. Group TitleBest ResponseYou've already chosen the best response.2
then use this chart for cosine dw:1358873950517:dw we are looking at the minus side since we got minus half. then 18060=120 degrees 180+60=240 degrees
 one year ago

AravindG Group TitleBest ResponseYou've already chosen the best response.1
@hannahg thats better :)
 one year ago

hannahg Group TitleBest ResponseYou've already chosen the best response.0
yes. so all the possible solutions will be pi, pi/3, 2pi/3?
 one year ago

.Sam. Group TitleBest ResponseYou've already chosen the best response.2
you still have sinx=0 to do
 one year ago

hannahg Group TitleBest ResponseYou've already chosen the best response.0
yes......! so 0?
 one year ago

.Sam. Group TitleBest ResponseYou've already chosen the best response.2
yes but dont forget about 180
 one year ago

.Sam. Group TitleBest ResponseYou've already chosen the best response.2
dw:1358874634831:dw
 one year ago

.Sam. Group TitleBest ResponseYou've already chosen the best response.2
since theta is 0, then you get 180
 one year ago

hannahg Group TitleBest ResponseYou've already chosen the best response.0
@.Sam. so what are all solutions in the interval??
 one year ago
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