graph of ycos x list all values on the interval 23 pi63pi4 t

graph of y=cos x, list all values on the interval [-23 pi/6,3pi/4], that satisfy ordered pair (x,-1/root 2)

Solution

y = cosx

ordered pair (x,-1/root 2)

Plug y = -1/sqrt2

cosx = -1/sqrt2

x = cos^-1(-1/sqrt2) interval [ -690 deg , 135 deg] --->

-23pi/6 ----IVrth quadrant and 3pi/4 is in IInd quadrant

All solution shoudl lie between the two:

x = pi -pi/4 = 3pi/4.No other solution exist in the given range [ -690 deg , 135 deg]

still