Question

IF sin 2A = cos ( A-30* ) where 2A is an acute angle. Find the value of A .

Answer 1

Answer:

45°

Step-by-step explanation:

sin 2A=cos(A-30°)

=>cos(90°-2A)=cos(A-30°)

now , 90-2A=A-30

=>90+30=3A

=>120=3A

A=120/3=45......so A =45°

Answer 2

The value of A = 40°

Given :

sin 2A = cos ( A - 30° ) where 2A is an acute angle

To find :

The value of A

Solution :

Step 1 of 2 :

Write down the given equation

Here it is given that

sin 2A = cos ( A - 30° ) where 2A is an acute angle

Step 2 of 2 :

Find the angle A

sin 2A = cos ( A - 30° )

⇒ cos ( 90° - 2A ) = cos ( A - 30° )

⇒ ( 90° - 2A ) = ( A - 30° )

⇒ - 2A - A = - 30° - 90°

⇒ - 3A = - 120°

⇒ A = 40°

Hence the value of A = 40°

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