1'6 Inverse Functions

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1.6 Inverse Functions

• A function evaluates x to find y and its inverse
  evaluates y to get back to x.
• The function/inverse relationship is correct only
  if f(x) y and f -1(y) x.
• Because this unique connection must exist, only
  one-to-one functions have inverses.
• A one-to-one function has no two x values that
  correspond to the same y, meaning
• that any horizontal line will intersect its graph
  no more than once.
• Functions that are constantly increasing or
  decreasing will pass the horizontal line test
  and,
• therefore, are always one-to-one.
• Once you have verified that a function is
  one-to-one, solve for x in terms of y.