Question

1 ) If sin 3A = Cos (A - 26°) , where 3A is an acute angle , find the value of A

☞︎︎︎ᴡɪᴛʜ sᴛᴇᴘs ☜︎︎︎​

Answer 1

Answer:

Answer

Given that

sin3A=cos(A−26)

cos(90−3A)=cos(A−26) [sinθ=cos(90−θ)]

Comparing angles

90−3A=A−26

−3A−A=−26−90

−4A=−116

A=

4

116

A=29

class 10 th boy -_-

Answer 2

sin3A=cos(A−26∘)sin3A=cos⁡(A−26∘)

⟹cos(90∘−3A)=cos(A−26∘)

⟹cos⁡(90∘−3A)=cos⁡(A−26∘)

⟹90∘−3A=A−26∘

⟹4A=116∘

⟹A=29∘

3A=3×29∘=87∘

Which is an acute angle

sin3A=sin(87∘)=cos(29∘−26∘)=cos(3∘)