Question

(A) Select and write the most appropriate alternative from those given below.
If Sin B = Cos(3B - 30) where 2B is an acute angle then the value of B =
[20°, 30°, 40°, 90°)​

Answer 1

Step-by-step explanation:

here is your answer

cos(90-theta)=sin theta

Answer 2

$\large{\colorbox{cyan}{\underline{\underline{\bf{\purple{☆▪ BE BRAINLY ▪☆}}}}}}$

Sin B = Cos ( 3B - 30 )

Cos ( 90 - B ) = Cos ( 3B - 30 )

Comparing the angles .

we get ,

90 - b = 3B - 30

-B - 3B = -30 - 90

-4B = -120

B = -120/-4

B = 30°