Tentukan nilai dari Cos 75° dan tan 15°

Cos 75
= cos (90-15)
= sin 15
= sin (45-30)
= sin45 cos30 – cos45 sin30
= √2/2 × √3/2 – √2/2 × 1/2
= √6/4 – √2/4
= (√6-√2)/4

tan 15
= sin15/cos15
= (√6-√2)/4 × 4/(√6+√2)
= (√6-√2)/(√6+√2)