Question 1062978
What is the value of cos−1 ⁡(−√2/2) in Quadrant II?

 cos−1⁡ (−√2/2)= __________°
<pre>In the 1st quadrant: {{{cos^- 1 (sqrt(2)/2) = 45^o}}}
In the 2nd quadrant, where cos < 0, the reference angle of {{{matrix(1,1, cos^- 1 (- sqrt(2)/2) = 90^o + 45^o = 135^o)}}}
Converting {{{135^o}}} to, radians, we get: {{{highlight_green(matrix(1,3, 135 * (pi/180), "=", 3pi/4))}}}