We know that
and this is the only point when sin and cos are equal lengths. Because both 
Now if the sin of 30° is a half that would mean that cos of 60° is also a half.
Hope this helps.
<u>r3t40</u>
-9 x 1/3
= -9/3
= -3
......................................
In solving algebraic expressions, there is an order in which to solve it.
1) perform the operation inside the parenthesis first
2) then perform the operation with the exponents
3) apply multiplication and division from left to right of the equation.
4) apply addition and subtraction from left to right of the equation.
Remember this: PEMDAS for easier recall. (parenthesis, exponents, multiplication, division, addition, subtraction)
What do u need help on? It gives u the answer which is X=10/3