Signs in the second quadrant

Exercise and reference answers

Questions

1. Question

   Three of these statements about an obtuse angle x are false.

   Choices

   1. Item

      cos x is negative for obtuse x

      Correct

      Yes

   2. Explanation

      sine stays positive in the second quadrant

      Item

      sin x is negative for obtuse x

   3. Explanation

      tangent is negative in the second quadrant

      Item

      tan x is positive for obtuse x

   4. Explanation

      an obtuse angle lies in quadrant 2

      Item

      an obtuse angle is in quadrant 1

Instructions

Three of these claims about an obtuse angle x are false. Fault them.