tan(90° + x).tan(270° +x) =
A.     − 1
B.   − tan x
C.   − cot x
D.   − cot2 x
E.   − tan2 x
F.   cot2 x
                     

[ 4-6768 - op net sinds 15.1.15-(E)-27.10.2023 ]

Translation in   E N G L I S H

tan(90° + x).tan(270° +x) = A.     − 1
B.   − tan x
C.   − cot x
D.   − cot2 x
E.   − tan2 x
F.   cot2 x

Oplossing - Solution

tan(90° + x).tan(270° + x) = tan(90° + x).tan(90° + x) = cot² (−x) = (−cot x)² = cot² x