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Homework Help: Finding primary trig ratios

  1. Oct 25, 2016 #1
    1. The problem statement, all variables and given/known data
    The question states to find the primary trig ratios for (7π)/4

    2. Relevant equations

    3. The attempt at a solution
    I got
    sin= (-√2)/2
    tan= -1
    csc= 2/(-√2)
    sec= 2/(√2)
    cot= -1

    I got all of them correct except for csc and sec, and I am unsure why the solutions are telling me
    csc = -√2
    sec = √2
    I thought my original answers were correct because csc is reciprocal of sin and sec is reciprocal of cos.
    Can someone help me make sense of this?
  2. jcsd
  3. Oct 25, 2016 #2


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    2017 Award

    Staff: Mentor

    Write ##2= \sqrt{2}\,\cdot\,\sqrt{2}## and cancel one root factor.
  4. Oct 25, 2016 #3


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    Staff Emeritus
    Science Advisor
    Homework Helper
    Gold Member

    Rationalize the denominators.
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