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Cant figure out how to verify this identity? Find f if f double prime (x)=sin(x)+cos(x), f(0)=6, fprime(0)=-1? Are the holes in my underwear due to a high velocity gas problem I have? How many kinds of 6-membered rings are in DNA? How do I calculate 1/6 into a decimal without a calculator? It is 0.167....but how?