## Welcome to H3 Maths

Blog Support for Growing Mathematicians

## Posts tagged with sine curve

### Sound Waves and Noise Cancelling

July21

Play the note A Play the (shifted) note A You may have seen advertisements for “noise reducing” headphones. Here’s a rough idea of how they work. First they figure out what kind of noise is reaching your ears. Essentially this means it figures out the sine waves of the ambient sounds. Then it creates additional […]

by posted under Uncategorized | tagged under , , , ,  |  Comments Off on Sound Waves and Noise Cancelling

### Hear Ye, Hear Ye, Math = Sound Waves!

July4

There is a lot of information on the web about sound waves and the mathematical patterns surrounding them. For example, the changes in air pressure produce sine curves such as this one below. Of course, there are complex formulae that apply in calculating sound effects. When we listen to a radio or TV we hear […]

by posted under Uncategorized | tagged under , , , ,  |  Comments Off on Hear Ye, Hear Ye, Math = Sound Waves!

### Touch Mathematics – cool curves

November2

by posted under Uncategorized | tagged under , , ,  |  Comments Off on Touch Mathematics – cool curves

### So…the slope changes on a curved graph

March11

So, you may have figured out that Calculus is quite useful when we are looking at the Mathematics of Change. If you hold your textbook in your hands then that is like standard mathematics…but, if you drop it onto the floor (or your head), then that is Calculus. Yes, Calculus has to do with motion […]

by posted under Uncategorized | tagged under , , ,  |  Comments Off on So…the slope changes on a curved graph

### Yes, Lombard St follows a Sine Curve

February13

So, wise mathematician, let’s connect our view of Lombard St with a Sine Curve. We can do this using (on Mac computers, etc.) a free application called Grapher (go to applications–>utilities–>Grapher) or check out the apps for iPhone and iPad here, or use one of the free online graphing tools. Anyway, when we combine the sine […]

by posted under Uncategorized | tagged under , , , , , , , ,  |  Comments Off on Yes, Lombard St follows a Sine Curve

### More Streetwise Maths

February13

Yes, keen Maths student – more street-wise Mathematics coming your way, again from San Francisco. It is Lombard Street, one of the crookedest streets in the world and a very popular tourist attraction. Click here to find out more information about this amazing street – one we went down in a large people mover and […]

by posted under Uncategorized | tagged under , , , , ,  |  Comments Off on More Streetwise Maths

#### Post Support

The graph on the left (Coronavirus) is for a time period of 30 days, while the one on the right (SARS) is for 8 months! Very poor graphical comparison and hardly relevant, unless it is attempting to downplay the seriousness of the coronavirus?

10 x 9 x 8 + (7 + 6) x 5 x 4 x (3 + 2) x 1 = 2020

NCEA Level 2 Algebra Problem. Using the information given, the shaded area = 9, that is:
y(y-8) = 9 –> y.y – 8y – 9 =0
–> (y-9)(y+1) = 0, therefore y = 9 (can’t have a distance of – 1 for the other solution for y)
Using the top and bottom of the rectangle,
x = (y-8)(y+2) = (9-8)(9+2) = 11
but, the left side = (x-4) = 11-4 = 7, but rhs = y+? = 9+?, which is greater than the value of the opp. side??
[I think that the left had side was a mistake and should have read (x+4)?]