# How to deal with second order time derivatives?

**URL:** <https://community.freefem.org/t/how-to-deal-with-second-order-time-derivatives/1580>\
**Category:** General Discussion\
**Created:** [March 6, 2022, 1:03pm UTC](https://community.freefem.org/t/how-to-deal-with-second-order-time-derivatives/1580 "2022-03-06T13:03:12Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![SamuelJosephs](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.freefem.org/samueljosephs/32/1046_2.png) [@SamuelJosephs](https://community.freefem.org/u/SamuelJosephs)\
**Post date:** [March 6, 2022, 1:03pm UTC](https://community.freefem.org/t/how-to-deal-with-second-order-time-derivatives/1580/1 "2022-03-06T13:03:12Z")

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Looking through the forum ([Approximation of the second order derivative](https://community.freefem.org/t/approximation-of-the-second-order-derivative/1465)) it seems as though P1 is inappropriate for second order and higher time derivatives. So how would I go about dealing with these? The examples only ever use first order.

Given these are very common in wave equations I find it hard to believe that FEM does not a have a way to deal with these, but on the off chance FEM is not suitable for second order time derivatives what is the suitable way to go around this?

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**Author:** ![frederichecht](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.freefem.org/frederichecht/32/15_2.png) [@frederichecht](https://community.freefem.org/u/frederichecht)\
**Post date:** [March 7, 2022, 3:02pm UTC](https://community.freefem.org/t/how-to-deal-with-second-order-time-derivatives/1580/2 "2022-03-07T15:02:10Z")

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The wave equation is a basic equation with second order derivative in times,  
so you can see the example:

[FreeFem++ users | Main \>\> WaveEquation](https://www.um.es/freefem/ff++/pmwiki.php?n=Main.WaveEquation)