Which of the following are identities? check all that apply. a. cos(x + y) + cos(x - y) = 2009 xcosy o b. cos(x + y) - cos(x - y) = 2 coexcosy c. sin(x + y) + sin(x - y) = 2cosxsiny d. tar(x - 25) = tan x

your question is incomplete, write all the numbers in the sequence that it tells you.  

step-by-step explanation:

if you was gonna solve for a, a is a   < -12

a) 0

step-by-step explanation:

i^413 x i^0 = 0 as any number multiplied by a zero is

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step-by-step explanation:

d would equal 12