Help me please this is due today help me

What basic trigonometric identity would you use to verify that sin x cos x tan x =1-cos^(2)x?

Can (3,5 and square root 34) be sides on a right triangle?

Which composition of similarity transformations maps polygon abcd to polygon a'b'c'd'? a dilation with a scale factor less than 1 and then a reflection a dilation with a scale factor less than 1 and then a translation a dilation with a scale factor greater than 1 and then a reflection a dilation with a scale factor greater than 1 and then a translation