Is this right ... its about trigonometry?

Question

if i have it wrong please corect it!

1. sin 5 pi/ 6 da answer i put is 1/2

2. sin 7 pi/ 6 the answer i put is 1/2

3. sin 11pi/6 the answer i put is -1/2

4. cos 5pi/6 the answer i put is sqrt3/2

5. cos 7pi/6 the annswer i put is -sqrt3/2

6. cos 11pi/6 the answer i put is -sqrt3/2

Answer 1

1. Correct

2. Wrong, -1/2

3. Correct

4. Wrong, -sqrt(3)/2

5. Correct

6. Wrong, sqrt(3)/2

(Note that in part 4, the negative sign should actually be outside the square root... otherwise your answer would be imaginary, which is wrong.)

Answer 2

1 correct

2.wrong,  1/2

3.correct

4. wrong, sqrt(-3)/2

5. correct

6. wrong, sqrt(3)/2

Answer 3

1 correct

2.wrong, actually 1/2

3.correct

4. wrong, actually sqrt(-3)/2

5. correct

6. wrong, actually sqrt(3)/2

sorry, but you have some more studying to do..