$1)$ Use the find$\_$root function in Figure $4-3$ to print the sum of approximations to the square root of $25,$ the cube root of $-8,$ and the fourth root of $16.$ Use $0\mathrm{.}001$ as epsilon.

$2)$ Write a function is$\_$in that accepts two strings as arguments and returns True if either string occurs anywhere in the other, and False otherwise.

Hint: you might want to use the built$-$in str operator in$.$

$3)$ Write a function to test is$\_$in$.$