To 2 decimal places, what is the value of the lower-right entry in the reflection matrix $Q_a $if a = 1.05?
Not even sure where to begin, is there a formula?
This is what I could find in my textbook
Okay, well the lower right entry of the matrix $q_a$ is $-\cos(2a)$. So plug in $a = 1.05$ and use a calculator to get an approximate value for $-\cos(2.10) \approx 0.50485$. Be sure to use 'radian' mode on your calculator. (Always assume angle measures for trigonometric functions are in radians unless explicitly told otherwise.)