Hi :)
I need to resolve equation f(x)=0 in the intervale (-pi,pi)
f(x)=sin(2x-pi/2)-1/2
I came here but i am not sure if it´s right.
sin(2x)-cos(2x)-3/2=0
Can anyone help, please ? :)
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OpenStudy (anonymous):
i help you
OpenStudy (anonymous):
thanks :)
OpenStudy (anonymous):
what grade you are in
OpenStudy (anonymous):
plesae
OpenStudy (anonymous):
are you still there?
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OpenStudy (anonymous):
yes
OpenStudy (anonymous):
what are are you in
OpenStudy (anonymous):
?
OpenStudy (anonymous):
-.-
OpenStudy (anonymous):
i am in second but i am not sure if it s same as in your country cause i am from Slovakia. I am 16 years old if it helps.
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OpenStudy (anonymous):
your in second grade
OpenStudy (anonymous):
yes
OpenStudy (anonymous):
why theying giving you that kind of work
OpenStudy (anonymous):
idk :) we have diffrent system (i am in bilingual class)
OpenStudy (freckles):
\[\sin(2x-\frac{\pi}{2})-\frac{1}{2}=0 \\ \sin(2x-\frac{\pi}{2})=\frac{1}{2} \\ \text{ Let } u=2x-\frac{\pi}{2} \\ \text{ so since we had } -\pi<x<\pi \text{ and } x=\frac{u}{2}+\frac{\pi}{4} \\ \text{ Then we need \to solve } \sin(u)=0 \text{ \in the interval } -\pi<\frac{u}{2}+\frac{\pi}{4}<\pi \\ -4\pi<2u+\pi<4\pi \\ -5\pi<2u<3\pi \\ \frac{-5\pi}{2}<u<\frac{3\pi}{2}\]
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OpenStudy (freckles):
So you need to solve sin(u)=0 in the interval (-5pi/2,3pi/2)