Question

Please solve this question


Take A = 60 and B = 30. Write the value of cosA , cosB and cos(A+B) . Is cos(A+B) = cosA + cosB​

Answer 1

given ,A = 60 ,B = 30

according to question,

cos( A + B ) = cos ( 60°+ 30° )

= cos90° = 0

now ,cosA + cosB = cos60° + cos30°

= 1 / 2 + √3 / 2 =( √3 + 1 ) / 2

so ,it shows that cos( A +B ) is not equal to

cosA + cosB.

●hope it helps ●

Answer 2

Solution.

CosA = 1/2
CosB =
$\sqrt{3} \div 2$
cos (A+B) = Cos (60+30)=Cos90=0


No cos (A+B) is not equal to cos A + Cos B

cos (A+B) = 0
and cosA+CosB =
$1 + \sqrt{3} \div 2$
So, LHS IS NOT EQUAL TO RHS .