Answer:
Step-by-step explanation:
2 cos x + √ 2 = 0
2 cos x = -√ 2
cos x = -√ 2 / 2
x = arcCos( -√ 2 / 2 )
so to solve we have to use "co-terminal " angles .. do you know what I'm saying? do you understand the words coming out of my mouth :DDDDD OKay back to math and not movie lines .. :P
x = arcCos( √ 2 / 2 )
x = 45 °
now find the "co terminal" angle that is on 45 ° but in the correct quadrant... since the -√ 2 is negative.. we now that we go down the y axis.. but also positive on the x axis.. soooo.. that put the angle in the 4th quadrant... so this is an angle of 315° if we go in the CCW ( counter clock wise ) direction but it's also -45° in the CW (clock wise ) direction
below is the table to remember the trig special angles
notice how it's 1,2,3,4 .. so it's super easy to remember.. the trig books don't show you this "trick" :P
copy and paste this to your computer some where handy
Sin(0) = 0/2 =0
Sin(30)=
/2 = 1/2
Sing(45) =
/2 =
/2
Sin(60)=
/2 =
/2
Sin(90)=
/2 = 1
Cos is exactly the same but counts backwards from 90°
Cos(90) = 0/2 = 0
Cos(60) =
/2 = 1/2
Cos(45) =
/2 =
/2
Cos(30) =
/2 =
/2
Cos(0) =
/2 = 1
<span>2x^2 - 2x - 1 = 0 a = 2, b = -2, c = -1 b^2 - 4ac = (-2)^2 - 4(2)(-1) = 4 + 8 = 12
so the answer is 12
</span>
F(x)=x^2+x+5
then
F(3) would be the function evaluated at x=3, or 17.
anytime you see F(3) it is just whatever formula you are looking at evaluated when the variable is equal to 3.
The answer is C. y = - 2x - 1
hope that helps!! :)