How Do You Integrate the Square of dx/dt?

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To integrate the square of dx/dt, the expression can be rewritten as ∫(dx/dt)(dx) instead of directly integrating (dx/dt)² dt. However, simply canceling dt leads to ∫(dx/dt)dx, which complicates matters since the result depends on the specific relationship between x and t. The integral's complexity varies based on the function x(t); for example, if x(t) = t², the integral is straightforward, while x(t) = e^(t²) results in a non-elementary integral. Understanding the dependence of x on t is crucial for determining the correct approach to the integration.
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Hey, not really homework but I am just having a total mind blank and would be grateful if someone could help me.
\int\left(\frac{dx}{dt}\right)^{2}dt=?
I even have the answer my brain is just refusing to play along though and I just can't picture how to work it out properly at the moment.
Thanks!
 
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try writing it as

\int \frac{dx}{dt} \frac{dx}{dt} dtinstead.
 
rock.freak667 said:
try writing it as

\int \frac{dx}{dt} \frac{dx}{dt} dt


instead.
Thanks for your reply.
In that case I don't have brain freeze I just don't know. I just want to cancel the dt's but then
I get
\int \frac{dx}{dt}dx
which I don't know how to handle.
 
It's not the sort of an expression where you can eliminate the t dependence. The answer depends on how x depends on t. E.g. if x(t)=t^2, then it's an easy elementary integral, if x(t)=e^(t^2), it's not an elementary integral.
 
Question: A clock's minute hand has length 4 and its hour hand has length 3. What is the distance between the tips at the moment when it is increasing most rapidly?(Putnam Exam Question) Answer: Making assumption that both the hands moves at constant angular velocities, the answer is ## \sqrt{7} .## But don't you think this assumption is somewhat doubtful and wrong?

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