Recent content by barryj

I have a leaf blower that states the sound level is 75dB. My question is, at what distance is this measured. It seems that as you get closer to the source, the dB number will increase drastically. If I double the distance from the source, then the power should go down by a factor of four or 6...

I was given a problem to use an array, not a matrix, to solve a system of equations. I have not heard of doing this and can not find any reference to how to do it. like... 2x+3y = 12, and 3x-4y = 14 How is this solved using an array or grid?

I have been trying to find the financial formula that will give the balance of a credit card debt as a function of time. Example, at 18% interest, if I pay $150 a month how long will it take me to pay off my debt. When I google, I get pointers to Excello functions. I want to know the exact formula.

I know that 1/sqrt(2) can be multiplied by sqrt(2)/sqrt(2) to give sqrt(2)/2 How can I do something similar with 1/cuberoot(2) ?? What is the trick?

[Mentor Note -- OP has requested that this clarification post be added to the end of this closed thread] The moderator closed part 1 before I could post the requested theorem. I have attached the figure and a copy of the theorem from a geometry book for those that are interested.

I agree with your calculations. I did a simulation using a cutout of the shower footprint and moving it as you did and get the same plot. The dots agree with your calculation. So it seems I can have a 19 inch bench. Good!.

You had best get another calculator.

No, there is a 120 degree angle at the 4/6 intersection and the lines do not meet at the same point. They are separated by 2 inches. This thread is getting silly. I am gone!

Actually, it was not my diagram. I copied it out of a geometry textbook. When I posted the diagram, I did not know if it was a right triangle or not.

The answer was not known in advance. One had to use the knowledge of the theorem to get the answer. The angle could be drawn as a right angle, an acute angle, or an obtuse angle. It would not make any difference in the solution.

I If you knew the theorem then it would not matter if the angle was close to a right angle or not. The surprising fact is that the "experts" here did not know the theorem otherwise they would have merely refreshed my memory of it.

So, you are saying that when solving a geometry problem I should get out my calipers and draw the diagram with precision?? No way. A general diagram is all that is necessary.

The drawing was accurate. As it turns out, what looks to be a right angle is in fact about 83 degrees. No, the student knew the theorem, applied it, and got the correct answer. There was no lucky guess here. How could anyone look at that diagram and guess the answer to be 12?? If they could then...

Well, the drawing must be accurate because my 15 year old student worked the problem in about 15 seconds. Go figure.

Well, when this problem was presented to my student ( I am a tutor) he worked it immediately. I did not recall the theorem he was using and this is why I posted on this forum. In fact, it took me a while to find the theorem in my geometry book as I did not know the proper name for it. I am...