Sin squared is equal to 1 - cos squared.
sin cubed + cos cubed (sin + cos)( sin squared - sin.cos + cos squared) (sin + cos)(1 + sin.cos)
There is no reason at all. For most angles sin plus cos do not equal one.
Note that an angle should always be specified - for example, 1 - cos square x. Due to the Pythagorean formula, this can be simplified as sin square x. Note that sin square x is a shortcut of (sin x) squared.
Cos^2 x = 1 - sin^2 x
2 x cosine squared x -1 which also equals cos (2x)
Sin squared, cos squared...you removed the x in the equation.
The deriviative of sin2 x + cos2 x is 2 cos x - 2 sin x
If tan 3a is equal to sin cos 45 plus sin 30, then the value of a = 0.4.
Multiply both sides by sin(1-cos) and you lose the denominators and get (sin squared) minus 1+cos times 1-cos. Then multiply out (i.e. expand) 1+cos times 1-cos, which will of course give the difference of two squares: 1 - (cos squared). (because the cross terms cancel out.) (This is diff of 2 squares because 1 is the square of 1.) And so you get (sin squared) - (1 - (cos squared)) = (sin squared) + (cos squared) - 1. Then from basic trig we know that (sin squared) + (cos squared) = 1, so this is 0.