Quadratic Trig Equation

[ginamarie313]

So, this one won't factor, so I use the Quadratic Formula, right?

8sin^2(x)+5sin(x)-1=0

 

[pka]

CORRECT!

 

[ginamarie313]

how do i plug it into the formula is my question

 

[stapel]

Same as always: a = 8, b = 5, c = -1, and x (or, in this case, sin(x)) is given by:

. . . . .\(\displaystyle \Large{\frac{-b\mbox{ }\pm\mbox{ }\sqrt{b^2\mbox{ }-\mbox{ }4ac}}{2a}}\)

Once you've solved for what sin(x) equals, then solve the resulting two trig equations for what x equals.

Eliz.