
Let
, so that
:

Now the ODE is separable, and we have

Integrating both sides gives

For the integral on the left, rewrite the integrand as

Then

and so


Given that
, we find

so that the particular solution to this IVP is

B. Neither/nor is the answer
4 units right and 4 units down
The amount of balls in a given layer can be found by squaring the layer it is in
4 layers
top layer (1st) is 1
2nd is 4
3rd layer is 9
4th is 16
add them up
1+4+9+16=30
30 in that pyramid
The number 17 has the code 21021