Find tg a and ctg a if sin a = 3/5.

From the formula sin ^ 2a + cos ^ 2a = 1, we express
cos ^ 2a = 1 – sin ^ 2a;
cos ^ 2a = 1 – (3/5) ^ 2;
cos ^ 2a = 1 – 9/25;
cos ^ 2a = 25/25 – 9/25;
cos ^ 2a = 16/25;
cos a = 4/5;
tg a = sin a / cos a;
tg a = 3/5: 4/5;
tg a = 3/5 * 5/4;
tg a = (3 * 5) / (5 * 4);
tg a = (3 * 1) / (1 * 4);
tg a = 3/4;
ctg a = cos a / sin a;
ctg a = 4/5: 3/5;
ctg a = 4/5 * 5/3;
ctg a = (4 * 5) / (5 * 3);
ctg a = (4 * 1) / (1 * 3);
ctg a = 4/3;
Answer: tg a = 3/4 and ctg a = 4/3.