Question

sin4A=cos(A-20), where 4A is an acute angle , find the value of A
​

Answer 1

We know that,

sinA=cos(90

o

−A)

Now, sin4A=cos(A−20

⇒cos(90 −4A)=cos(A−20 )

⇒90o −4A=A−20

o

⇒110

o

=5A⇒A=22

o

Answer 2

Answer:

22°

Step-by-step explanation:

sin 4A = cos (A - 20)

=> cos (90 - 4A) = cos (A - 20)

=> 90 - 4A = A - 20

=> 5A = 110

=> A = 22°

.°. The answer is A= 22°