Question

if a=60°and B=30,° veryfy that
cos (A + B) = cos A cos B - sin A sin B​

Answer 1

Step-by-step explanation:

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

cos90=cos60 cos30 - sin60 sin30

0 = (1/2)(√3/2)-(√3/2)(1/2)

0 = (√3/4)-(√3/4)

0=0

so, verified that cos(A+B) = cosA cosB-sinA sinB

Answer 2

Answer:

_*༆✿ ANSWER ✿༆*_

A=60∘ B=30∘

cos( A + B ) = cos A × cos B − sin A sin B

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

cot 20

0 = 1/2 ×√3/2 − √3/2 × 1/2

0 = 0

Hence Verified , that cos (A + B) = cos A cos B - sin A sin B.