Why does -sin (pi/2+pi/2) = 0 ? can you explain why this is ?
and how do i other sin( and cos( calculations with two variables is there a trick?
1 * sin (pi/6
cos (pi/3*pi/6)
the above are just examples of different variations, i may have to calculate can you explain a way to calculate as on the calculator they give wrong answers

Which of the following would be an accurate picture of the earth during the summer time of the northern hemisphere?

Find the number of grams of hcl needed to react completely with .50 moles of magnesium.

Inside a flashbulb, oxygen surrounds a thin coil of magnesium. when the flashbulb is set off, a chemical reaction takes place in which magnesium combines with oxygen to form magnesium oxide. which of the chemical equations matches the reaction above? a. mg + o2 mgo2 + energy b. 2mg + o mg2o + energy c. 2mg + o2 2mgo + energy d. mg + o mgo + energy