Sunday
May 19, 2013

# Posts by yuni

Total # Posts: 26

math
if a & b are perpendicular vectors, show that a)(a+2b).(a-b)=|a|^2-2|b|^2 b)(a+b).(a-b)=|a|^2+|b|^2 *how to show it?just multiply it?if yes where does||come from? does||show that it should be a value?

math
Find the interior angle formed by points A(1,5,3) , B(-2,3,7) , C(3,2,5). does this mean i need to find all the 3 angles of triangle?

math
the position vectors of the point A,B & C respect to O are a=3i-2j+4k, b=i+3j-4k, c=-2i+5j-3k. Find a)the angle between a+b and a-b b)lamdar if vector a is perpendicular to b+lamdar k.

math
prove cos(x+y) / cos(x-y) = (1-tan x tan y)/(1+tan x tan y)

chem
rate=k[A2][B2]^2. by how much would the rate change if: i) [A2] is doubled? ii) [B2] is halved? *does the rate change equal with k?

chem
the atom of element A has 2 electrons in its highest energy level N. a)what is the special name given to elements in the same gp as A? i answered as alkali earth metal because the valence electron is 2. am i right?

chem
150 cm3 0.24 M naoh solution react with excess al(no3)3, calculate the mass of saodium aluminate produced. al(no3)3 + 4naoh -> naalo2 + 3 nano3 +2h20 i got 0.738g.. is my answer correct? if im wrong could u show me the calculation?

biology lab
im sorry but b4 this i already seacrh at the internet but i didnt found what i want. so i hope there will be another answer coming on.

biology lab
how to know from the experiment if the oxygen produced as a result of carbon fixation or electron transport? my experiment result show that average bubble/min for tap water is 4.7 while NaHCO3 is 1.8.

biology lab
-rate of photosyhthesis in presence of light intensity & CO2. ~A : sodium bicarbonate in darkness pH b4 xperiment-9 " @ 20 min- 8 " 60 min- 8 ~B: sodium bicarbonate in room light pH b4 xperiment-9 " @ 20 min-9 " 60 min-8 ~C: sodium bicarbonate 20 cm from li...

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