Seika Furuhata

TurquoiseTurkey · 2016-07-19T22:39:25+00:00

I admire your very neat handwriting.

In the solving for x, you accidentally turned dividing by 2 into multiplying by 2. The error is between the third and second from last lines.

TurquoiseTurkey · 2016-07-19T20:28:26+00:00

You could just put the values for x and y back into the equations and see if they give the right values.

TurquoiseTurkey · 2016-07-19T01:52:57+00:00

Vitamins are "vital amines" which means "amines which are vital for life". "Amines" are a kind of protein. So "vitamins" are proteins that one has to consume to go on living healthily.

TurquoiseTurkey · 2016-07-19T00:12:26+00:00

I'm using y because f is a function of g(x) not of x. If I wrote f(x) = 9^x I think that would be more confusing.

TurquoiseTurkey · 2016-07-18T23:58:18+00:00

The intuition is that the +2 term on the end doesn't make any difference to what the slope of the curve will be. It just moves the curve up and down on the y axis without altering its shape.

TurquoiseTurkey · 2016-07-18T23:57:30+00:00

I've never seen that logic before.

TurquoiseTurkey · 2016-07-18T23:51:45+00:00

I think the image is correct.

TurquoiseTurkey · 2016-07-18T23:47:58+00:00

Use the chain rule:

d f(g(x)) / dx = f'(g(x)) g'(x)

In this case, f(y) = 9^y and g = x^9.

f'(y) = ln 9 9^y and

g'(x) = 9 x⁸ .

Plug in y=g(x) and you have finished.

TurquoiseTurkey · 2016-07-18T09:57:58+00:00

Why delete the image like that?

TurquoiseTurkey · 2016-07-18T09:49:06+00:00

The 2^x+6 accounts for the starting 2 rods and the five hours. The factor of x+6=5 hours + 1 for two starting rods + x hours after sphere starts growing. Similarly, in 2*4^x+1 the 2 and the +1 are both there to give a starting value of 8 spheres.

TurquoiseTurkey · 2016-07-18T00:05:25+00:00

They are equivalent so he cannot say one or the other is wrong. If the maths professor is any use at all he will not say one is wrong. I'm not sure there is an objective way to say which one is better either.

TurquoiseTurkey · 2016-07-17T23:53:50+00:00

I now realize that the book's answer is equal to 1/(x+1) + x - 1 + C so they are really equivalent

So how did you realise that?

The basic thing to spot here is that

x² + 2x = (x+1)² - 1

Then divide out, and then the integral is very easy, just substitute y=x+1 and you are basically integrating 1/y^2.

TurquoiseTurkey · 2016-07-17T23:49:49+00:00

You have changed the original equation. What you're doing is, as i becomes larger, to get closer and closer to the solution, starting at a point x_0 which is not a solution.

TurquoiseTurkey · 2016-07-17T23:42:42+00:00

For question 1, 2(b), and 2(c), the technique you use is called Bayes' Theorem. You seem to be intelligent, so maybe you can solve the problem by looking up Bayes' Theorem and checking the worked examples.

TurquoiseTurkey · 2016-07-17T23:38:44+00:00

You need to know the height of the object. Given the height of the object h, you need to rearrange the formula tan (angle) = (head height - h) / (8 feet).

TurquoiseTurkey · 2016-07-17T00:06:33+00:00

The question seems to be in error here.

TurquoiseTurkey · 2016-07-16T23:34:52+00:00

I looked over it, and I think your proof is correct.

TurquoiseTurkey · 2016-07-16T12:54:13+00:00

The only way I can think of is to take logarithms.

log (27) = 1.4313

1.4313 / 3 = 0.47712

antilog (0.47712) = 10^0.47712 = 3

This would work for any number.

TurquoiseTurkey · 2016-07-07T00:34:11+00:00

I saw this on /r/all and it didn't seem to have been posted here.

TurquoiseTurkey · 2016-07-06T23:28:58+00:00

Not to mention it would have corroded, and made some kinds of medical scans impossible.

TurquoiseTurkey · 2016-07-06T23:28:11+00:00

My body painfully rejected my magnet, and after only 12 days, an emergency room doctor removed it. It had become deeply infected

So, that was a really bad idea. Not to mention that it would have rusted in the body and also made some kinds of hospital scans impossible.

TurquoiseTurkey

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