Question

IS IT RIGHT TO SAY COS(60+30)=COS60 COS30 -SIN60 SIN30?​

Answer 1

Answer:

yes it is correct

cos(30+60)=cos60 cos30-sin60 sin30

Step-by-step explanation:

hope its helpful

Answer 2

L.H.S

$\sf \cos(60° + 30°) = \small90° \:$

$\: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \sf = 0$

R.H.S

$\sf \cos60° \: cos30° - sin60° \: sin30°$

$\large \sf = \frac{1}{2} \times \frac{ \sqrt{3} }{2} - \frac{ \sqrt{3} }{2} \times \frac{1}{2}$

$\large \sf= \cancel{\frac{ \sqrt{3} }{4}} - \cancel{\frac{ \sqrt{3} }{4} }$

$\sf = 0$

$\sf \cos60° \: cos30° - sin60° \: sin30° = 0$

L.H.S = R.H.S