added timeWeightedAvg function

content/influxdb/v2.0/reference/flux/stdlib/built-in/transformations/aggregates/timeweightedavg.md

@@ -0,0 +1,53 @@
+---
+title: timeWeightedAvg() function
+description: The `timeWeightedAvg()` function outputs the timeWeightedAvg of non-null records as a float.
+menu:
+  influxdb_2_0_ref:
+    name: timeWeightedAvg
+    parent: built-in-aggregates
+weight: 501
+related:
+  - /influxdb/v2.0/reference/flux/stdlib/built-in/transformations/aggregates/integral/
+---
+
+The `timeWeightedAvg()` function outputs the time-weighted average of non-null records
+in a table as a float.
+Time is weighted using the linearly interpolated integral of values in the table.
+
+_**Function type:** Aggregate_  
+_**Output data type:** Float_
+
+```js
+timeWeightedAvg(unit: "_value")
+```
+
+## Parameters
+
+### unit
+Time duration used when computing the time-weighted average.
+
+_**Data type:** Duration_
+
+## Examples
+```js
+from(bucket: "example-bucket")
+  |> range(start: -5m)
+  |> filter(fn: (r) =>
+    r._measurement == "cpu" and
+    r._field == "usage_system"
+  )
+  |> timeWeightedAvg(unit: 1m)
+```
+
+## Function definition
+```js
+timeWeightedAvg = (tables=<-, unit) => tables
+  |> integral(
+    unit: unit,
+    interpolate: "linear"
+  )
+  |> map(fn: (r) => ({
+    r with
+    _value: (r._value * float(v: uint(v: unit))) / float(v: int(v: r._stop) - int(v: r._start))
+  }))
+```

content/influxdb/v2.0/reference/release-notes/flux.md

@@ -27,8 +27,9 @@ InfluxDB until the next InfluxDB v2.0 release._
 - Improve window errors.
 - Add BigQuery support to [`sql` package](#).
 - Add `TypeExpression` to `BuiltinStmt` and fix tests.
-- Time-weighted average ([`timeWeightedAvg()` function](#)).
-- Integral with linear interpolation.
+- Time-weighted average ([`timeWeightedAvg()` function](/influxdb/v2.0/reference/flux/stdlib/built-in/transformations/aggregates/timeweightedavg/)).
+- Update [`integral()`](/influxdb/v2.0/reference/flux/stdlib/built-in/transformations/aggregates/integral/)
+  with linear interpolation.
 - Make experimental tracing an attribute of the context.
 
 ### Bug fixes