Learn about Trigonometry word problems - part 2
Welcome back. I was just jugging through the—the hairy math of this problem which I think we’re almost done. But as I was saying, we’re just simplifying this and 25xsin² of 15+cos² 15 well, that’s an identity, right? I remembered, I undistributed this 25 so sin²+cos² of the same angle is 1 so then I can simplify this too and now I will now change colors just to be obituary.
So, 25+100-100cos of 15º and this is what M² is equal to and I used the variable M because it stands for nothing relevant to this problem and that equals 125-100cos to 15º. Now I have to use a calculator if I want to get a real answer but the—the area—the possibility for error is much lower now that I’ve hopefully simplified it. So I can use my calculator and to see the cosine of 15º— cosine of 15º I’ll write that down here, you could just use a calculator or table to figure that out.
It is equal to .96593 so this term would be 125-100 times this, right? So what a 100 times this? Well that’s just -96.593 or I'll just write 100 times the cosine if 15º and now let me use the trusty calculator to figure out what that is. So if I say, 125-96.593 I'll get 28.407 so I have M² is equal to 28.407 and so M is equal to the square-root so that's going to be 5 point something right? Square root, 5.329—so 5.33, M is equal to 5.33 and we’re done.
The poor guy, he’s got to figure out the right direction to go and he probably has to think about the current and all of that but he hasn’t asked us that question so we won’t answer—so, but—all he has left to go is 5.33 miles so he’s—he’s only have to go an extra .33 miles and he would have had he’d gone in the right direction from the gecko.
Hopefully, that makes some sense. If it doesn’t, well, not much I can do but maybe you can re-watch this video. Have fun!
Transcription by:
Scribe4you Transcription Services