`s=int ("velocity") dt`
[We could use s or h for height in this problem.]
We need to find:
We put the following (since any other possible substitution doesn't actually work):
`u = ln(t^3+ 1)`
We need to find `(du)/(dt)`. We have a function of a function, so we'll need to use the Chain Rule to find that derivative. We substitute a new variable, `v`:
`v=t^3+1`, giving `u = ln v`.
Now `(dv)/(dt) = 3t^2` and `(du)/(dv) = 1/v = 1/(t^3+1)`.
Using the Chain Rule, we get:
` = 1/(t^3+1) xx (3t^2)`
Writing this as a differential in the form we need for the integral, we have:
Going back to the original integral with the substitution `u = ln(t^3+ 1)`, we get:
`u^2 = ln^2(t^3+ 1)`
`=1/3 xx u^3/3+K`
Now, since the height is `0` when `t = 0`, we substitute and obtain `K = 0`.
At `t=10`, the height of the space vehicle will be: