How to combine 3 tables using entity framework and LINQ?

Without using tables, what is the value of 2sin30degree?

• 1, without using tables, what is the value of 2sin30degree? 2, without using tables, what is the value of (sin60degree cos60degree)? 3, without using tables, what is the value of ...show more

• Answer:

  These are key values to remember, when you want to save time: sin(30) = (√1)/2 = 1/2 sin(45) = (√2)/2 sin(60) = (√3)/2 sin(90) = (√4)/2 = 2/2 = 1 cos(90-x) = sin(x) for example, cos(60) = sin(90-60) = sin(30) = 1/2 tan(x) = sin(x)/cos(x) for example tan(30) = sin(30)/cos(30) = sin(30)/sin(60) = (1/2)/[(√3)/2] = 1/(√3) = (√3)/3 --- For your questions: 2 * sin(30) do it directly from the values to be remembered. sin(60) cos(60) sin(60) is from the list to be remembered. cos(60) = sin(90-60) = sin(30) --- sine and cosine are cyclical functions, with a cycle of 360 degrees sin(0) = sin(360) sine is an "odd function" this is just a strange way to say sin(-x) = -sin(x) for example, if you are looking for sin(330), you can rewrite this as sin(360-30) because the cycle is 360, the 360 can be replaced by 0 sin(0 - 30) = sin(-30) = -sin(30) = -1/2 sin^2(330) = (-1/2)^2 (careful, the square will be positive) cosine is an "even function" meaning cos(-x) = cos(x) cos(330) = cos(-30) = cos(30) (when doing the "square of a square root"... they cancel each other out) (for example (√5)^2 = 5 )