Question

cot cot^-1 (21π/4)​

Answer 1

Answer:

we rewrite the original problem as

arctan

⎛

⎜

⎜

⎝

1

tan

(

−

π

4

)

⎞

⎟

⎟

⎠

Then

arctan

⎛

⎜

⎜

⎝

1

tan

(

−

π

4

)

⎞

⎟

⎟

⎠

=

arctan

(

1

−

1

)

=

arctan

(

−

1

)

=

−

π

4