polynomial approximation of mercator conversion

mercator.go

package main

import (
	"fmt"
	"math"
	"math/rand"
	"testing"
)

func main() {
	x := testing.Benchmark(func(b *testing.B) {
		for i := 0; i < b.N; i++ {
			ddLat := -855113 + rand.Float64()*(855113*2)
			y1 := ddLat / 180 * math.Pi
			y2 := math.Log(math.Tan(y1) + (1 / math.Cos(y1)))
			wmLat := y2 / math.Pi * 20037508.342789
			_ = wmLat
		}
	})
	fmt.Println(x)

	//https://www.numberempire.com/taylorseriesexpansion.php
	//%pi-log(tan((%pi/4)+(x/2))) =>
	//%pi-x-x^3/6-x^5/24-(61*x^7)/5040-(277*x^9)/72576-(50521*x^11)/39916800-(41581*x^13)/95800320
	x = testing.Benchmark(func(b *testing.B) {
		for i := 0; i < b.N; i++ {
			ddLat := -855113 + rand.Float64()*(855113*2)
			y1 := ddLat / 180 * math.Pi
			y2 := y1 + (math.Pow(y1, 3) / 6) +
				(math.Pow(y1, 5) / 24) +
				(math.Pow(y1, 7) * 61 / 5040) +
				(math.Pow(y1, 9) * 277 / 72576) +
				(math.Pow(y1, 11) * 50521 / 39916800) +
				(math.Pow(y1, 13) * 41581 / 95800320)
			wmLat := y2 / math.Pi * 20037508.342789
			_ = wmLat
		}
	})
	fmt.Println(x)
}