Question

5. If A = 60°, B = 30° then prove that Cos (A+
B) = Cos A Cos B - Sin A Sin B.​

Answer 1

Answer:

please follow me

Step-by-step explanation:

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Answer 2

Answer:

To prove: Cos(A+B) =Cos A CosB - Sin A Sin B

Cos(60+30) =Cos 60 * Cos 30 -Sin 60 * Sin 30

Cos 90 = 1/2 * √ 3/2 - √3/2 * 1/2

0=√3/4 -√3/4

0=0

RHS= LHS

HENCE PROVED

Step-by-step explanation:

Cos 0 = 0

Cos 30 = √3/2

Cos 60 =1/2

Sin 60 = √3/2

Sin 30 = 1/2