Year 11 Trig help please (1 Viewer)

[markuz_73]

Having trouble with this question:
Q)
solve for 0 = < x = < 360 :
sin2xtanx - tanx + 2sinx - 1 = 0

cannot get it. help would be appreciated

 

[Thecorey0]

Well I cannot get it either. I am probably missing something very simple though. Looking at its graph though, and using newtons method, the solutions seem to be not exact i.e. not simple fractions with pi's. You will have to wait until a smarter person comes around.

 

[markuz_73]

thanks for the effort anyways but i finally got it.. quite simple, think we were just over looking simple factorisation
here's the solution if your interested

2sinxtanx - tanx + 2sinx - 1 = 0

tanx(2sinx - 1) + 2sinx - 1 = 0

(2sinx - 1)(tanx + 1) = 0

therefore:
2sinx - 1 = 0 or tanx + 1 = 0

then you just solve from there to get x = 0, 60, 180, 300, 360

thanks again

 

[Thecorey0]

That is why I could not do it then, you wrote the question wrong. You wrote 'sin2xtanx' not '2sinxtanx'.

 

[markuz_73]

fuck.. sorry... i just spent a good hour yesterday with that wrong question..
i'm an idiot.. sorry lol

 

[addikaye03]

Having trouble with this question:
Q)
solve for 0 = < x = < 360 :
sin2xtanx - tanx + 2sinx - 1 = 0

cannot get it. help would be appreciated

Is that sin2x or sinx, in your working you used sinx...

I think you'll find thats what made it so hard, i spent like 20 mins on it yesti lol