Question

If SinA=4/5 find the value of Sin2A and Cos2A

Answer 1

Answer:

Sin A = 4/5

Cos A = 3/5 [ You can check it by Pythagoras theorm ]

Sin 2A

= 2sinAcosA

= 2 × 4/5 × 3/5

= 24/25

Cos 2A

= cos^2 A - Sin^2 A

= (3/5) ^2 - (4/5)^2

= 9/25 + 16/25

= 25/25

= 1