# K9-47G

Senior Members

39

• #### Last visited

• Birthday 03/23/1988

## Profile Information

• Location
Atlanta, Georgia
• College Major/Degree
Physics.
• Favorite Area of Science
Genetics/Evolution.

• Quark

10

1. ## The vegetative state and awareness

That's interesting.
2. ## Matt Ridley's "Genome"

No, it's not a novel. He talks a lot about findings from the Human Genome Project. I suppose as far as books are concerned it's comparable to much of Dawkin's works. Informational, but with a more laid-back approach.
3. ## Matt Ridley's "Genome"

Has anyone here read it? What did you think of it?

I got 4.3
5. ## Optimization

This is one optimization problem that I just cant figure out. I'll post what I have... A hiker at point A on a straight road wants to reach, in the shortest time, a point B located 6 miles from the road and 10 miles from point A. The hiker's speed on the paved road is 4 mph and only 2 mph off the road. How far should he continue on the road before heading in a straight line for the point B? I am pretty sure I would have to use the pythagorean theorem because if you draw the problem you get a triange with two sides given. Plus I denoted $dr/dt$ to be the speed on the road which is 4 mph, and $do/dt$ to be the speed off road which is 2 mph. I just don't know how to find my objective function. Any help would be appreciated.
6. ## Ending the 0.999~ = 1 debates

I noticed that if I type .9999999999 (ten nines) into my TI-83 calculator and press enter, it gives me the answer to be .9999999999 (ten nines), But if I type .99999999999 (eleven nines) into my calculator and press enter it gives the answer to be one. I suppose my TI-83 rounds to the 10th decimal place.
7. ## Derivatives: Some Questions...

For number 3, I thought I would use the logarithmic power rule (not sure of the real name) and therefore the exponent, sinx, can be written as the first term in problem. Then I used the product rule to find the derivative.. $y= (\ln x)^{\sin x}$ is the same as $\sin x\ln x$
8. ## Derivatives: Some Questions...

Ok, thanks a lot.
9. ## Derivatives: Some Questions...

Can you tell if those answers are right?
10. ## Derivatives: Some Questions...

1) Find $\frac{d}{dx} log(lnx)$ I assume that the log has a base of 10, so I got $\frac{1}{x(lnxln10)}$ 2) Find the slope of the line tangent to the graph $cos(xy)=y$ at $(0,1)$ $-sin(xy)(y)+(xy')=y'$ $-ysin(xy)=y'-(xy')$ $\frac{-ysin(xy)}{1-x}=y'$ Then I just keep getting 0 when I substitute (0,1) in... 3) If $y=(lnx)^{sinx} x>1,$ Find $y'$ $sinxlnx=sinx\frac{1}{x}+(cosx)(lnx)$ $\frac{sinx}{x} +cosxlnx$ $1+cosxlnx$
11. ## Harder than what they Look?

I think the second one has to do with the purple squares in the background.
12. ## Hard Question!

This problem reminds me of the many examples that Richard Dawkins gave in his book, The Selfish Gene.
13. ## 1?

11131221133112132113212221 whew.
14. ## derivative of sin(sin(sinx))

Can you please check if my answer is correct. $y=sin(sin(sinx))$ $y'=cos(sin(sinx))cos(sinx)cosx$ (My calculus professor doesn't want our answers simplified.)

ok, thanks.
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