What is the answer no links or I will report

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

Eis the midpoint of line segment ac and bd also line segment ed is congruent to ec prove that line segment ae is congruent to line segment be

Me! i really need to get this right before 9. prove the divisibility of 7^6+7^5-7^4 by 11. use factoring so you get a number times 11. just tell me the number. i need this done asap