Calculus, c'mere

[Neche]

Question on a test today

45sin^2(x)-7sin(x)-10

Find roots and where it occurs on the period [0,pi]

I got roots as 5/9, and -2/5.

Occurs at arcsin(5/9),pi-arcsin(5/9), pi+arcsin(2/5), 2pi-arcsin(2/5).

Then it tells me my roots are wrong, but occurrence is right. So what the fuck, how could I get that wrong but the occurrence right?

 

[Strid]

Any way you could scan your work, or rework it for me (don't leave out a single step even the small ones)? I can't tell where you went wrong based off the provided information. I'm a bit rusty too so it's possible I wont be able to help at all.

It could just be that you're Canadian, semi joking of course

 

[Neche]

Well I figured that out, I haven't see this next screen since highschool and I have no notes on it, if anyone could point me in the right direction on how to solve for B that would be ace, not do it for me, but give and example on how to or whatever.

Don't mind the 5 heh, it's not right

 

[exodusamphi]

o gawd i hated calculus. good luck

 

[Xalioniaf]

Seeing this only increases my anticipation for next semester.

 

[Jojojo]

a) b = 8, because that way the limit as x->3 = 5 from the left and from the right.

b) b = -2. Set the limit from the left equal to the limit from the right and you will find that b = -2 and b = 8...but at b=8 f is continuous, so b=-2 is our only answer. Check this by seeing that if b=-2 then the limit from the left = limit from the right but is not equal to 5--that is, f(3).

c) Um, none? It's impossible to get the limit from the left equal to infinity or negative infinity.

d) This one I say (-infinity, -2)U(-2, 8)U(8, infinity) but I'm not 100% sure. What I did was set the limit from the left side not equal to the limit from the right. I got b to be everything but -2 and 8, which makes sense.

 

[Neche]

Jojojo, what part of the function do I take the limit from? I'm still unclear