# How do you find the intervals of increasing and decreasing using the first derivative given #y=sinx+cosx#?

##### 1 Answer

The function is increasing on intervals of the form

#### Explanation:

The derivative of

You can check that

You can check that

The answer above follows from these observations.

You can confirm this visually by looking at the graph.

graph{sin(x)+cos(x) [-10, 10, -5, 5]}