Question

If tanA=12/16,find sin 2A​

Answer 1

Solution:

First, we need to draw a right triangle to represent the given trigonometric ratio. (Kindly refer to the attached photo for the figure.)

Second, we need to determine the length of the unknown side.

In this case, the unknown side is the hypotenuse. Since the length of the opposite side is 12 and the length of the adjacent side is 16, then the length of the hypotenuse is

$c = \sqrt{16^{2} + 12^{2}}$

$c = 20$

After this, we need to know the trigonometric identity of sin 2A in order to solve for its value.

We know that,

sin 2A = 2 sin A cos A

Then, we need to determine the values of sin A and cos A.

Based on the figure (attached photo), the values of sin A and cos A are

sin A = opposite side / hypotenuse

sin A = 12/20

sin A = 3/5

cos A = adjacent side / hypotenuse

cos A = 16/20

cos A = 4/5

Finally, we can now solve for the value of sin 2A by substituting the values of sin A and cos A to the trigonometric identity of sin 2A.

Therefore, the the value of sin 2A is

sin 2A = 2 sin A cos A

sin 2A = 2(3/5)(4/5)

sin 2A = 24/25