An equation is called an identity if it is valid for value(s) of the variable. The equation
2x = x + x
is an algebraic identity, and the equation
sin2(x) + cos2(x) =
is a trigonometric identity.

If a and b are the measures of two first quadrant angles and sin a = 4/9 and sin b = 2/5 find sin(a+b).

Element x decays radioactively with a half life of 8 minutes. if there are 450 grams of element x, how long, to the nearest tenth of a minute, would it take the element to decay to 37 grams?

The equation |pl = 2 represents the total number of points that can be earned or lost during one turn of a game. which best describes how many points can be earned or lost during one turn? o o -2 2 oor 2 -2 or 2 o