SOLUTION: If x = 30 degree, then which expression is equivalent to 1/2? a. -sin x b. sin x c. -cot x d. cot x

Algebra ->  Angles -> SOLUTION: If x = 30 degree, then which expression is equivalent to 1/2? a. -sin x b. sin x c. -cot x d. cot x      Log On


   

Question 739202: If x = 30 degree, then which expression is equivalent to 1/2?
a. -sin x
b. sin x
c. -cot x
d. cot x
Answer by KMST(5328) About Me  (Show Source):
You can put this solution on YOUR website!
sin%2830%5Eo%29=1%2F2 cos%2830%5Eo%29=sqrt%283%29%2F2 cot%2830%5Eo%29=cos%2830%5Eo%29%2Fsin%2830%5Eo%29=sqrt%283%29

No need to memorize that. Just picture an equilateral triangle with side length 1.
All the angles in that triangle measure 180%5Eo%2F3=60%5Eo.
According to the Pythagorean theorem, 1%5E2=%281%2F2%29%5E2%2BAP%5E2 --> 1=1%2F4%2BAP%5E2 --> AP%5E2=1-1%2F4=3%2F4 --> AP=sqrt%283%2F4%29=sqrt%283%29%2Fsqrt%284%29=sqrt%283%29%2F2