WEBVTT

1
00:00:00.000 --> 00:00:03.657
Here is the problem: e to the power x equals 1.

2
00:00:04.107 --> 00:00:09.808
Solve for x numerically (the equation contains functions such as sin, log or roots).

3
00:00:10.607 --> 00:00:12.128
Start with the equation.

4
00:00:12.578 --> 00:00:14.645
Rewrite as f(x) equals 0.

5
00:00:15.095 --> 00:00:31.152
This equation is not polynomial, so solve it numerically. Scan x from negative 10 to the power 9 to 10 to the power 9 for sign changes of f and for points where the graph touches the axis, then narrow each one down. Every root is checked by substituting it back.

6
00:00:31.602 --> 00:00:36.734
Found 1 solution in [−10 to the power 9, 10 to the power 9].

7
00:00:37.534 --> 00:00:39.752
So the answer is x equals 0.

8
00:00:40.201 --> 00:00:48.978
Values marked approximately are numerical approximations accurate to about 10 significant digits. Every value was checked by substitution.

9
00:00:49.778 --> 00:00:56.268
x equals 0: left side equals 1, right side equals 1, which checks out.
