Which of the following trigonometric expressions is equivale

Which of the following trigonometric expressions is equivalent to the x-coordinate of the terminal point (squareroot 2/2, squareroot 2/2)? cos (pi/3) sin (pi/6) sin(pi/4) cos(pi/6)

Solution

given (x,y)=(2 /2 ,2 /2)

r=[x²+y²]

r=[(2 /2)²+(2 /2)²]

r=[(2 /4)+(2 /4)]

r=[(4/4)]

r=1

x coordinate=rcos

2 /2 =1cos

cos =2 /2

we know when x,y >0

=/4

from the options sin(/4) =2 /2