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Thread: Adding Frac Trig Fcns: Going from X2/Tan(55) + X2/Tan(75)=87120 to 5.16X2/5.329=87120

  1. #1

    Adding Frac Trig Fcns: Going from X2/Tan(55) + X2/Tan(75)=87120 to 5.16X2/5.329=87120

    I am reviewing for a certification for work and I am unsure about one of the steps in the provided solution. The following are steps in the solution:

    1) X2/Tan(55) + X2/Tan(75)=87120
    2) 5.16X2/5.329=87120

    Can someone help me see how they are getting from step 1 to step 2? Is there a trig identity at work?

  2. #2
    Elite Member
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    If I had to guess, I'd guess that [tex]\tan(55)\cdot\tan(75) = 5.329[/tex]

    What do you suppose happens if we add the two tangents?

    We are finding a Common Denominator so the two fractions can be added.
    "Unique Answers Don't Care How You Find Them." - Many may have said it, but I hear it most from me.

  3. #3

    I figured it out, thanks tkhunny!

    First thing I checked was tan55 x tan75 and somehow got 25... switching over from a TI-89 to an HP35s using RPN has me miscalculating all sorts of stuff.

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