Need help with correction of my answers

[duffymercy]

Hello, I have some practice problems. I tried to solve by myself but I don't think it's %100 correct. Can you help me to confirm my answers?

 

[duffymercy]

I found my mistake for page 3;
dy/dx should be

[MATH](sin(t)+tcos(t))/(cost(t)-tsin(t))[/MATH]
so slope is [MATH](4+pi)/(4-pi)[/MATH]

 

[duffymercy]

I found convex&concave for page 4,

x =-infinite ------------(-1) ------------+infinite
f(x)= down-------------O-----------------up

 

[Steven G]

1st problem looks good.
Some comments: you never defined x which is a major mistake. You went onto say therefore f(x) =...
f(x) did not follow from your work. You can, if you choose to, define f(x) =...

 

[duffymercy]

1st problem looks good.
Some comments: you never defined x which is a major mistake. You went onto say therefore f(x) =...
f(x) did not follow from your work. You can, if you choose to, define f(x) =...

Thanks a lot, I will fix them.