WEBVTT

1
00:00:00.000 --> 00:00:03.738
Here is the problem: 2 to the power x equals 10.

2
00:00:04.188 --> 00:00:09.772
Solve for x numerically (the equation contains functions such as sin, log or roots).

3
00:00:10.572 --> 00:00:12.035
Start with the equation.

4
00:00:12.485 --> 00:00:14.598
Rewrite as f(x) equals 0.

5
00:00:15.048 --> 00:00:31.174
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
00:00:31.624 --> 00:00:36.744
Found 1 solution in [−10 to the power 9, 10 to the power 9].

7
00:00:37.544 --> 00:00:43.361
So the answer is x approximately 3.321928095.

8
00:00:43.811 --> 00:00:52.391
Values marked approximately are numerical approximations accurate to about 10 significant digits. Every value was checked by substitution.

9
00:00:53.191 --> 00:01:01.782
x equals 3.3219281: left side equals 10, right side equals 10, which checks out.
