# Check another trig behaviour

#### aisha

$$y=2\cos (\frac {-1} {2}x + 90 ) -3$$

I changed the original function to

$$y=2\cos [\frac {-1} {2} (x-180)] -3$$

period=-4pi
amplitude=2
max=-1
min=-5
range={y:-5<=y<=-1}
domain={x:XER}
vertical displacement 3 units down
horizontal translation 180 units left

Last edited:
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#### HallsofIvy

Homework Helper
We can't tell- there is no "x" in the original function.

#### iNCREDiBLE

aisha: do not confuse radians and degrees.

#### aisha

I dont think im confused about radians and degrees some of my trig functions have radians in them so to make things simpler I convert to degrees but in this question i havent done any converting that 90 is in degrees.
sorry I added the x in the original function.

#### aisha

Did i do this question correctly?

#### TD

Homework Helper
Yes, seems correct although I think the horizontal displacement is to the right.

#### LeonhardEuler

Gold Member
If the original question had 90 in it, then you did it correctly except for the direction of the horizontal translation. If the original question had $\frac{\pi}{2}$ in it, then the value of the horizontal translation is off too.

#### aisha

thanks so much the original question does have 90 degrees in it. You are right the horizontal translation should be to the right NOT LEFT!

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