# Can I do that in calculus? (canceling the dt terms in the numerator and denominator)

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NODARman
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Hi, just wondering if that's possible in calculus.
(See the attachment)

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Gold Member
MHB
TL;DR Summary: .

Hi, just wondering if that's possible in calculus.
(See the attachment)
What you wrote was essentially correct. But...

In reality? No. The derivative notation ##\dfrac{d \theta }{dt}## is not actually a fraction so you cannot cancel the dt's.

However, in practice you can "cancel" the dt's. It's a similar effect to the chain rule: ##\dfrac{d \theta }{dx} = \dfrac{d \theta }{dt} \cdot \dfrac{dt}{dx}##. Again, there is no real cancellation, but it appears that way.

Mathematicians in the 1800s spent a great deal of time showing how you can treat a differential element as a fraction. Most of the time you can get away with it.

-Dan

DaveE, vela and NODARman