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trig equation qn (2 Viewers)

Masaken

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Yeah I got +- pi/2 +2npi, but theres also the other two solutions for pi/6+2npi tho...
so when there's cos2x + |sinx| = 0, one of the cases is sinx <0, where x is in the domain of (pi, 2pi) (for sinx is equal than or > 0, x is in the domain [0, pi].

you get cos2x - sinx = 0, then simplify that to a quadratic which factors to (sinx+1)(2sinx-1) = 0. bear in mind since sin x < 0 and considering the given restrictions sin x has to be between [-1,0]. so when you get sinx=-1 and sinx=1/2, you can only take -1 as 1/2 lies outside that region, and thus pi/6 isn't a solution, same applies for sinx > 0 (pretend there's a line under the >) except you would get sinx=1 and sinx=-1/2
 

Average Boreduser

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so when there's cos2x + |sinx| = 0, one of the cases is sinx <0, where x is in the domain of (pi, 2pi) (for sinx is equal than or > 0, x is in the domain [0, pi].

you get cos2x - sinx = 0, then simplify that to a quadratic which factors to (sinx+1)(2sinx-1) = 0. bear in mind since sin x < 0 and considering the given restrictions sin x has to be between [-1,0] because of the unit circle. so when you get sinx=-1 and sinx=1/2, you can only take -1 as 1/2 lies outside that region, and thus pi/6 isn't a solution, same applies for sinx > 0 (pretend there's a line under the >) except you would get sinx=1 and sinx=-1/2
I just died of death from math overload. I'm gonna have sit down.
 

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