diff --git a/CHANGELOG.md b/CHANGELOG.md
index ba1f118c3..81d5f5164 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4282,6 +4282,28 @@ A total of 2 issues were closed in this release:
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+
+#### [@stdlib/math/base/special/vercos](https://github.com/stdlib-js/stdlib/tree/develop/lib/node_modules/%40stdlib/math/base/special/vercos)
+
+
+
+
+
+##### Features
+
+- [`a4b2764`](https://github.com/stdlib-js/stdlib/commit/a4b276428bdc454a9412550375813f92bd242540) - add C implementation for `math/base/special/vercos` [(##2397)](#2397 )
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#### [@stdlib/math/base/special/versin](https://github.com/stdlib-js/stdlib/tree/develop/lib/node_modules/%40stdlib/math/base/special/versin)
@@ -4666,6 +4688,7 @@ A total of 28 people contributed to this release. Thank you to the following con
+- [`a4b2764`](https://github.com/stdlib-js/stdlib/commit/a4b276428bdc454a9412550375813f92bd242540) - **feat:** add C implementation for `math/base/special/vercos` [(##2397)](#2397 ) _(by Gunj Joshi)_
- [`06f8b4a`](https://github.com/stdlib-js/stdlib/commit/06f8b4ad6fd804cd127387fa6a645cce0ee05250) - **feat:** add C implementation for `math/base/special/versin` [(##2398)](#2398 ) _(by Gunj Joshi)_
- [`c811882`](https://github.com/stdlib-js/stdlib/commit/c8118827f71ca602ccfea2721df03afbbd3857e5) - **feat:** add C implementation for `math/base/special/cosd` [(##2393)](#2393) _(by Gunj Joshi)_
- [`806075b`](https://github.com/stdlib-js/stdlib/commit/806075b124d1ab4fb7a541c117e0c7b6399a08b9) - **feat:** add C implementation for `math/base/special/hacoversin` [(##2387)](#2387) _(by Gunj Joshi)_
diff --git a/base/special/vercos/README.md b/base/special/vercos/README.md
index c176a76ed..9eb8aee3f 100644
--- a/base/special/vercos/README.md
+++ b/base/special/vercos/README.md
@@ -93,6 +93,94 @@ for ( i = 0; i < x.length; i++ ) {
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+
+* * *
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+
+
+## C APIs
+
+
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+
+### Usage
+
+```c
+#include "stdlib/math/base/special/vercos.h"
+```
+
+#### stdlib_base_vercos( x )
+
+Computes the [versed cosine][versed-cosine] of a `number` (in radians).
+
+```c
+double out = stdlib_base_vercos( 0.0 );
+// returns 2.0
+
+out = stdlib_base_vercos( 3.141592653589793 / 2.0 );
+// returns 1.0
+```
+
+The function accepts the following arguments:
+
+- **x**: `[in] double` input value.
+
+```c
+double stdlib_base_vercos( const double x );
+```
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+
+
+### Examples
+
+```c
+#include "stdlib/math/base/special/vercos.h"
+#include
+
+int main( void ) {
+ const double x[] = { 0.0, 0.523, 0.785, 1.047, 3.14 };
+
+ double y;
+ int i;
+ for ( i = 0; i < 5; i++ ) {
+ y = stdlib_base_vercos( x[ i ] );
+ printf( "vercos(%lf) = %lf\n", x[ i ], y );
+ }
+}
+```
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