Question

Evaluate the following sin 105 + cos 105

Answer 1

Heyy mate ❤✌✌❤

Here's your Answer...

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Sin 105 + Cos 105 can be written as.

=>Sin(60+45) + cos(60+45)

=[sin60cos45 +cos60sin45] + [cos60 cos45 - sin60sin45]

=cos 60 sin 45 +cos60 cos45

=1/2   *  1/sqrt2   +  1/2  * 1/sqrt2

=1/sqrt2

=cos45.
✔✔

Answer 2

sin 105° + cos 105°

cos (90° - 105°) + cos 105°

cos 15° + cos 105°

cos C + cos D = 2(cos(C+D)/2)(cos(C-D)/2)

2cos(120°/2)cos(90°/2)

2cos60°cos45°

2(1/2)cos45°

=cos45°