# Posts by mtd

Total # Posts: 5

science
I believe the noble gas group or Group O. Hopefully someone can verify that. I apologize if that is wrong.

math
Take the two equation two unknown down to one unknown by either adding or subtracting the second equation from the first so that one of the uknowns is removed. 2x+y=5 + x-y=1 -------------- 3x=6 x=2 Then plug the newly found x value into one of the equations to find y. In this...

Math (Trig)
let me try to type it out again, my apologies. Original problem is--Prove the following: 1- cot^2 x ----------- = cot^2 x tan^2 x - 1 That is how the problem actually looks.

Math (Trig)
sorry, another I can't figure out Show that (1-cot^2x)/(tan^2x-1)=cot^2x I started by factoring both as difference of squares. Would I be better served by writing in terms of sine and cosine? Such as: [1-(cos^2x/sin^2x)]/[(sin^2x/cos^2x)-1]=(cos^2x/sin^2x)

Math (Trigonometry)
square root(a^2 -u^2) where a>0, let u=(a sinx) where -pi/2<x<pi/2 answer is (a cosx) and I don't know how to get there