# Transforming arctan into arcsin: atan2asin

### 5.23.11 Transforming arctan into arcsin: atan2asin

The atan2asin command transforms any atans in an expression to asins, using the identity

arctan(x) = arcsin

⎛
⎜
⎜
⎜
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⎝

x

√

1+x2

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- atan2asin takes one argument:
  expr, an expression containing inverse trigonometric functions.
- atan2asin(expr) returns expr with any atans replaced by the appropriate asins.

#### Example.

Input:

atan2asin(atan(x))

Output:

arcsin

⎛
⎜
⎜
⎜
⎜
⎝

x

√

1+x2

⎞
⎟
⎟
⎟
⎟
⎠