Question

Cos90degrees cos30 degrees + sec-squared45degrees sin30degrees - cos270degrees sin180degrees

Answer 1

Explanation:

`\cos 90 \cos 30 + \sec^2 45 \sin 30 - \cos 270 \sin 180`

But we know that

`\cos 90 = \cos 270 = \sin 180 = 0`

and

`\sin 30 = (√(3))/(2) \:\:\text{and}\:\: \sec 45 = √(2)`

so this leaves us with just

`\sec^2 45 \sin 30 = (√(2))^2 \left((√(3))/(2) \right)= √(3)`