Let’s Find the ANGLE – Basic Trig Functions (sin, cos, tan)

Back in 1970, senior year of high school, I was thinking what am I ever going to need trig for. Fast forward a few years and I find out that it is necessary (or at the very least quite helpful) when you are laying out roof rafters for a house. I still love math. Numbers never lie.

Great the way you explained. I have watched your show and you are great. Thank you sir. I am a senior person but love your classes. Will watch again and again to enjoy your teaching methods. All the best.

This has helped during trying to get my GED thank you ❤️ I finally found a helpful video to explain these problems I still am still struggling with... I am not distracted I am focused on this because I have been trying to get this done... Thank you

Thank you for your time and video, we are covering trigonometry as we speak. It was very helpful to me. Thanks.

Thank you very much ! You explain very good, I have learned some technically difficult things to learn in Trigonometry from you Sir, you have been very helpfull !

Thank you so much for this. I want to know more. I hated Maths before. Now, I'm 55 and I'm learning for my students.

That's a good lesson thanks John😊

I really enjoyed the video. I asked that question, where am I going to use this. Without that you are just moving numbers on a page with no purpose. I started looking into these equations when I was trying to figure the angle of a splayed leg on a stool. I found the lengths by using “pitch or run and rise.” I marked that out using my framing square and then used a protractor. If I don’t have those things with me then I am stuck. Your explanation is easy to follow. I am glad you stressed taking good notes.

Actually I had fun solving this using Dyalog APL instead of a calculator. The hardest part (took me about two minutes because my APL was rusty) was converting arctan into APL. Then of course because all APL trig functions are expressed in radians I had to convert rads to degrees, another 30 seconds. Great fun! I don't use trig much so I like to refresh on the basics every now and then.

I was looking for a way to compute arctan(x) without using a table (as done by an electronic calculator), hoping this video would do that. Turns out arctan (x) can be expressed as a polynomial expansion series of (x) called the Maclaurin series approximation for arctan: arctan (x) = x - x^3/3 + x^5/5 - x^7/7 + ... (where ... means more terms and arctan(x) is in radians). Example1: arctan (1) = 1 - .33 + .20 - .14 = 0.73 radians, compared to the actual value arctan (1) = pi/4 or 0.78 radians or 45 degrees. Example2: arctan (.714285) = .714285 - .121477 + .037186 - .013552 = 0.616443 radians or 35.3 degrees (as in the video example). The series is infinite; the more terms you compute, the more accurate the result.

Calculated by using sinus X= 35,53°, also by calculating with tangens

Why 90° angle is drawn as box? I think it depends on country. Some ppl are drawing circle with dot.

Thanks, just writing a gravity simulator and have never used the ATN function on BASIC before. LET ANGLE=DEG(ATN(B/A))

If the tangent = opp/adj why do you take the inverse to get the answer?

I came on here trying to figure the angle to cut 2x4s for an unconventional slant roof. I did finally figure it out, but I had to watch the video 3 or 4 times because you yak too much. That's criticism, not insult. Thanks for the info.

Question. Is the answer is the answer 35.53 degrees or 35 degrees 53 minutes?

First of all love the channel. But I'm a little confused with this problem and would welcome help from the creator of this vid or anyone else.   So when I first viewed this problem I thought there was a way to solve it without using all of the trig functions. Here's my thought process. All triangles have a total of 180 degrees (at least in euclidean geometry). Since it's a right triangle we know that the angle opposite the hypotenuse is 90, that means that the sum of angle x and the other acute angle (let's call it y) equals 90. Now I made one intuitive leap that the ratio of the lengths of the sides is the same as the ratio of the angles opposite those sides. This yielded the rather simple algebraic equation and substitution : x+y=90 and so x + 7/5x = 90. Solving that: 2.4x = 90 and x = 37.50. The angles of the whole triangle would be 37.50, 52.50 and 90, which totals 180. But the video says the answer using the trig functions is 35.53 for x. So I was close but not right. Where did I go wrong? I checked, and checked my math over and over. The only thing I can think of, is that the intuitive leap was incorrect, that the ratio of angles is not equal to the ratio of side lengths opposite them? Or am I missing something else? Please help, this is bugging the crap out of me. Where did I go wrong? Thanks in advance.

Stay on Topic !

u saved me thank you legend

Rise over run, inverse tangent. 5/12 pitch to the roof. what is the angle of the rafter, the angle of the face cut to the ridge and what is the length of the rafter if the building is 24 feet wide? Who needs trig? No Speed Squares allowed.