Question

Is it right ti say cos (60°+30°)=cos 60° cos 30° sin 60° sin 30° •

Answer 1

Answer:

yes

Step-by-step explanation:

as

60+30=0

Answer 2

Answer:

We know that,

⇒ cos (A + B) = cos A cos B - sin A sin B

= $\frac{1}{2}$ x $\frac{\sqrt{3} }{2}$ - $\frac{\sqrt{3} }{2}$ x $\frac{1}{2}$

= $\frac{\sqrt{3} }{2} - \frac{\sqrt{3} }{2}$ = 0

⇒ cos (60° + 30°)

We know that,

= cos (A + B) = cos (60 + 30)

= cos 90°

⇒ 0

Hence, Yes it is right to say that

cos(60° + 30°) = cos 60°cos 30° − sin 60° sin 30°

⇒ LHS = RHS