Question

Which expression equals -1?

Answer 1

Option D. is correct.

Explanation:

`\cot ^(\left(2\right))\left(73^(\circ \:)\right)-\csc ^(\left(2\right))\left(73^(\circ \:)\right)\\`

`\csc \left(73^(\circ \:)\right)=(1)/(\sin \left(73^(\circ \:)\right))`

`=\cot ^2\left(73^(\circ \:)\right)-\left((1)/(\sin \left(73^(\circ \:)\right))\right)^2`

`\left((1)/(\sin \left(73^(\circ \:)\right))\right)^2 = \left(1)/(\sin^2 \left(73^(\circ \:)\right))\right`

`=\cot ^2\left(73^(\circ \:)\right)-(1)/(\sin ^2\left(73^(\circ \:)\right))`

Which is the same as...

`-1`