Added: 4 years ago
From: khanacademy
Views: 39,593
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  • Really interesting problem thanks alot.

  • I understand EVERYTHING!.. until 4:55 i dont get the bit where he got the 23 knots(wat is that?) anyways.. and how did he knw that that length was 23t?? isnt 23 the speed! not the distance... ??? and why is 't' there?? wat does t stand for??

    and lastly 'x t'?? wat is thatttttttttttttttt???????????­???????????????

    plz help. quick my exam is next week!!

  • @rAiNiEpUn007 23 knots was given already. T is time. 23t is distance since distance= speed multiplied by time. x is the speed of the other boat.

  • i get how he figured out the problem, just don't know why he used the 75 degree angle to solve it instead of the 15 degree angle, he could have used sine function to do it too couldn't he?

  • @Inferno0619 He could have chosen either angle, but choosing the 15 would've ALSO led to tan (rather than sin like you asked) because the known sides are opposite and adjacent. Using that knowledge leads you to ... tan (15) = x / 23, and I assume you can figure out the rest :)

  • Love your vids. I am 65 and refreshing my memory for an upgrade to my marine licence. I am enjoying learning again, I like your teaching method so thanks for posting these videos.

  • can any1 solve my problems if i post here??

  • The answer is around 6.2 knots

  • Thanks, I got the same answer!

  • Also got 3.956, 1.06, and 4.095 for the distances (in KM I guess?)

  • Whilst learning trig from your videos, I spent like 20 mins trying to solve for the time and distances. I'd highly appreciate it if anyone could check my math.

    For the time (t) it took for them to meet, I got t=.172, or 10.3 mins.

  • Comment removed

  • You'd have to know the distance between Milwaukee and Grand Haven before you could solve for the time.

  • If tan (75) = 3.732 (in degrees) this would make the speed of the small smuggling craft = 23/3.732 = 6.163 knots.

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