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How can I check my solar eclipse glasses to be sure they are safe? If cot0=2, what is the value of sec0/csc 0? Why is the sum of infinite series from n=2 to infinity of (6)/(n^2-1)=(9/2)? Need to locate a similiar bridge accrossing small rocky stream in California or Westcoast. Please see picture.
Thanks.? How big in terms of numbers would the human population be in 500 years?