Question

Evaluate cos 75 ............................

Answer 1

ANSWER:----------------

{ cos (a + b) = cos a.cos b - sin a.sin b}

{cos(75)=cos(30+45)=cos30⋅cos45−sin30⋅sin45=}

= (√32)(√22)−(12)(√22)=√6−√24

hope it helps ...thanks...

Answer 2

HEYA ❤️

HERE'S YOUR ANSWER !!

cos 75° = cos (30° + 45°)

= cos 30° cos 45° - sin 30° sin 45°

= (√3/2) (1/√2) - (1/2) (1/√2)

= √3/2√2 - 1/2√2

on solving and rationalizing, we get

(√3 - 1)√2 divided by 4

so we get

√6-√2 divided 4

further √6 can be written as √3 × √2

on putting the values

√2 = 1.414

√3 = 1.732

we finally get

= 0.25

HOPE IT HELPS ❤️