ANSWER
[tex]{ \tan }^{ - 1} (1) = 45 \degree[/tex]
Or
[tex]{ \tan }^{ - 1} (1) = \frac{\pi}{4} [/tex]
EXPLANATION
We want to evaluate:
[tex] { \tan }^{ - 1} (1)[/tex]
We can use scientific calculator to evaluate this directly to obtain:
[tex]{ \tan }^{ - 1} (1) =45\degree[/tex]
Or
[tex]{ \tan }^{ - 1} (1) = \frac{\pi}{4} [/tex]
You could have also let:
[tex]x = { \tan }^{ - 1} (1)[/tex]
Then,
[tex] \tan(x) = 1[/tex]
The angle whose tangents is 1 is
[tex]x =45\degree[/tex]
Or
[tex]x = \frac{\pi}{4} [/tex]
