tentukan nilai sin 75° + cos 75° ?

sin75
= sin(30 + 45)
= sin30 cos45 + cos30 sin45
= (1/2) (1/2)√2 + (1/2)√3 . (1/2)√2
= (1/4)√2 + (1/4)√6
= (1/4)(√2 + √6)

cos75
= cos(30 + 45)
= cos30 cos45 - sin30 sin45
= (1/2)√3 . (1/2)√2  -  (1/2) . (1/2)√2
= (1/4)√6 - (1/4)√2
= (1/4) (√6 - √2)

sin 75° + cos 75°
= (1/4)(√2 + √6) + (1/4) (√6 - √2)
= (1/4) (2√6)
= (1/2)√6