Find Sin A, tg A, ctg A if СosA = 0.6.

Let’s remember the main trigonometric identity:
(sin A) ^ 2 + (cos A) ^ 2 = 1
Knowing the cosine, we can find the sine:
sin A = √ (1 – (cos A) ^ 2)
sin A = √ (1 – 0.6 ^ 2)
sin A = √ (1 – 0.36)
sin A = 0.8
Now we know the sine and it will not be difficult for us to find tg A and ctg A:
tg A = sin A / cos A
ctg A = cos A / sin A
tg A = 0.8 / 0.6 = 4/3
ctg A = 0.6 / 0.8 = 3/4
Answer: sin A = 0.8; tg A = 4/3; ctg A = 3/4.