### Home > PC > Chapter 4 > Lesson 4.3.2 > Problem4-140

4-140.

Verify that $\frac { 1 } { 1 + \operatorname { tan } ^ { 2 } x } + \frac { 1 } { 1 + \operatorname { cot } ^ { 2 } x }= 1$ by simplifying the left side and using the Pythagorean identities.