Question about the fundamental theorems of calculus
\[d/dx \int\limits_{-3}^{1}\]
2t^3+3dt
your question doesn't seem right and if it is you are taking derivative of a constant...
there are options
and derivative of a constant is...
0
the second equation i wrote is part of the first one
I don't see an equation I see an expression
\[\int\limits_{-3}^{1} f(t) dt=\text{ some constant number } \\ \frac{d}{dx} \int\limits_{-3}^{1} f(t) dt=\frac{d}{dx}(\text{ some constant number} )=0\]
\[d/dx \int\limits_{-3}^{1} (2t ^{3}+3) dt\]
the choices are a. 2t^3 + 3 b. 56.0 c. 5 d. -28.0 e. none of these
do you have anymore questions on this one?
do you understand that the definite integral is going to be a constant ?
by d/dx next to that means we have to differentiate that result
yes
the derivative of any constant is 0
yep
but that isnt one of the choices unless there are more steps
i thought you listed none of these
none of these means none of the above
and 0 wasn't listed above so it has to be none of these
I know that F'(x) = f(x) right?
yes assuming F is some antiderivative of f
yah
so would that make it option a?
no derivaitve of a constant is not 2t^3+3
or is that different because it is f(t) instead of f(x)
\[\int\limits_a^b f(t) dt \text{ if this exists } \\ \text{ will be a constant if the upper\lower limit is not a variable }\]
\[F'(x) = d/dx (\int\limits_{a}^{x} f(x) dt) = f(x)\]
that is one of the fundamental theorems that i think im supposed to use
do you understand both of your limits are constants? not one of them is a variable
okay so none of these
i would only use that if one was a variable?
but fine if you want to use \[\frac{d}{dx} \int\limits_a^{x} f(t) dt=f(x) \\ \text{ then rewrite } \int\limits_{-3}^{1} f(t) dt \text{ as } \int\limits_{-3}^{x} f(t)+\int\limits_x^{1} f(t) dt =\int\limits_{-3}^{x}f(t) dt-\int\limits_{1}^{x} f(t) dt \\ \text{ so } \frac{d}{dx}(\int\limits_{-3}^{1} f(t) dt)=\frac{d}{dx}(\int\limits_{-3}^{x} f(t) dt-\int\limits_1^x f(t) dt) \\ \frac{d}{dx} \int\limits_{-3}^{1} f(t) dt=\frac{d}{dx} \int\limits_{-3}^{x } f(t) dt - \frac{d}{dx } \int\limits_1^{x} f(t) dt \\ \frac{d}{dx} \int\limits_{-3}^1 f(t) dt=f(x)-f(x) \\ \frac{d}{dx} \int\limits_{-3}^{1} f(t) dt=0\] but all of this work is totally unnecessary given we should know that the definite integral we are differentiating is a constant
yah you are right thankyou
you could use the fundamental theorem if one or more is a variable however if both are constant you could shove a variable in between those constants and do fundamental theorem of calculus but it is totally totally unnecessary
if you feel like it could you help me with one more
sure
first what is h'(x)?
use that fundamental theorem of calculus you were trying to mention before
okay one sec
f(t)?
well f(x)
h'(x)=f(x)
so we are looking at a graph of h'(x)
what is f(x) though?
f(x) is the graph which is also h'(x)
f(t) is the actual function so is f(x) some other function or the curve?
looking at the graph where is h'(3) aka f(3)
okay
-5
h'(3)=f(3)=-5 but choice a says h'(3)>0
but -5>0 is not true
not true okay what about the other 2?
one at a time
okay to find the critical number of h' we must look at h'' and find when h''=0 to find the critical numbers of h we must look at h' and find when h'=0 let's do the latter first because it is much easier
so we are actually looking at choice 3 right now
h(x) has a relative maximum at x=5? trying to see if this is true or false... so we need to find the critical numbers of h we start by finding h' (we done this; it is f which is the graph given) we look to see where h'=0
what x values do you have h' is 0?
this means at what x values does h' aka f cross the x-axis
2,4, and 6
right so x=5 isn't even a contender to be a max or min since it wasn't even a critical number of h
wait but it is the highest point within that area so woldnt that make it a relative max? and the global max would be at 1
you are looking at the graph of h' not the graph of h
oh okay
for part 2 you actually don't need to find the second derivative like I mentioned since the graph of h' is given the only problem is x=2 is also not a relative max of h' h' has a global max/relative max occurring at x=1 h' has a global min/relative min occurring at x=3 h' has a relative max occurring at x=5 And there looks like h' has a relative min occurring at x=6.6 approximately
That first line does say the function f(t) is graphed below right? like there isn't like a prime symbol I'm missing there right?
that is what it says
so it seems like the only one that is true is III
I'm pretty sure none of them are true The critical numbers of h is when h'=0 which is when x=2,4,6 x=5 wasn't included in those numbers
these all seem false to me
oops x=0,2,4,6,8 if you want to include the endpoints
so none of them are true?
nope
okay well thank you for your help!!
weird both questions you asked are none of these
yah that is why i was trying to make sure that you were right because i never really get those kind of answers
all of these would have been right: h'(3)<0 h'(x) has a relative maximum at x=5. h(x) has a relative maximum at x=2.
wait they are all RIGHT?
like if the sign in the first one has been switched or if the x=2 and x=5 has been switched in the last two options
no you aren't reading what I wrote if you think that :p
your choices were h'(3)>0 h'(x) has a relative maximum at x=2 h(x) has a relative maximum at x=5 which are all incorrect
oh nevermind
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