How do you simplify cos(2 tan ^-1 x)?
1 Answer
Use double angle formula to remove coefficient inside the cos, then rearrange standard trig definitions to make the trig function match the inverse trig function inside the bracket
Explanation:
Recall the double angle formula:
Then
So we now have a trig function of an inverse trig function. If we can express our
By definition,
By definition,
So