Quick Q [trig function] (1 Viewer)

[Jago]

sin 3x = -1

??

someone explain the process to me. ta.

 

[Pace_T]

3x = 180+90 or 360-90. (all stations to center, pick the negative quadrants, make sure that when u put it in the calculator u put it as positive, the negative will come into play when u determine which quadrants to use, in this case it is T and C, the two quandrants where the sin ratio will have a negative value.)

= 270

x = 90 degrees or pi/2

 

[Jago]

right. thanks.

 

[blackfriday]

sin3x = -1
this means there are three periods between 0 and 360
so
3x= 270, 270+360, 630+360
= 270, 630, 990
x= 90, 210, 330

 

[HellVeN]

Yeah but it doesn't restrict the domain to 0<=x<=2PI so couldn't there potentially be infinite solutions?
Therefore I'd think you'd need to leave it as a general trig solution?

 

[Jago]

no no, doman was 0 - 2pi, i just forgot to put it in.

 

[HellVeN]

Well hooray for domains .