diff --git a/src/decn/decn_tests_trig.cpp b/src/decn/decn_tests_trig.cpp
index c8b53a6..3217287 100644
--- a/src/decn/decn_tests_trig.cpp
+++ b/src/decn/decn_tests_trig.cpp
@@ -1,26 +1,41 @@
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
 
 #include <string>
 #include <boost/multiprecision/mpfr.hpp>
 #include <catch2/catch.hpp>
 #include "decn.h"
+
+#include "decn_tests.h"
+
 namespace bmp = boost::multiprecision;
 using Catch::Matchers::Equals;
 
 
 static void trig_test(void (*operation)(void), bmp::mpfr_float (*mpfr_operation)(bmp::mpfr_float x),
-	const char* a_str, int a_exp, double rtol, double atol)
+	                  double rtol, double atol)
 {
-	CAPTURE(a_str); CAPTURE(a_exp);
-	build_dec80(a_str, a_exp);
+	//build mpfr float
+	bmp::mpfr_float::default_precision(50);
+	decn_to_str_complete(&AccDecn);
+	CAPTURE(Buf);
+	bmp::mpfr_float a_actual(Buf);
+	//calculate
 	operation();
 	decn_to_str_complete(&AccDecn);
 	CAPTURE(Buf);
-
-	bmp::mpfr_float::default_precision(50);
-	std::string a_full_str(a_str);
-	a_full_str += "e" + std::to_string(a_exp);
-
-	bmp::mpfr_float a_actual(a_full_str);
+	//calculate actual
 	a_actual = mpfr_operation(a_actual);
 	CAPTURE(a_actual);
 
@@ -32,50 +47,92 @@ static void trig_test(void (*operation)(void), bmp::mpfr_float (*mpfr_operation)
 		bmp::mpfr_float diff = abs(a_actual - calculated);
 		CHECK(diff < atol);
 	}
-
 }
 
-static void sin_test(
-	const char* a_str, int a_exp, double rtol=5e-3, double atol=1e-3)
+
+static void sin_test(double rtol=5e-3, double atol=1e-3)
 {
-	trig_test(sin_decn, [](bmp::mpfr_float x) -> bmp::mpfr_float {return sin(x);}, a_str, a_exp, rtol, atol);
+	CAPTURE("sin test");
+	trig_test(sin_decn, [](bmp::mpfr_float x) -> bmp::mpfr_float {return sin(x);}, rtol, atol);
 }
 
-static void cos_test(
-	const char* a_str, int a_exp, double rtol=5e-3, double atol=1e-3)
+static void sin_test(const char* a_str, int a_exp, double rtol=5e-3, double atol=1e-3)
 {
-	trig_test(cos_decn, [](bmp::mpfr_float x) -> bmp::mpfr_float {return cos(x);}, a_str, a_exp, rtol, atol);
+	CAPTURE(a_str); CAPTURE(a_exp);
+	build_dec80(a_str, a_exp);
+	sin_test(rtol, atol);
 }
 
-static void tan_test(
-	const char* a_str, int a_exp, double rtol=5e-3, double atol=1e-3)
+
+static void cos_test(double rtol=5e-3, double atol=1e-3)
 {
-	trig_test(tan_decn, [](bmp::mpfr_float x) -> bmp::mpfr_float {return tan(x);}, a_str, a_exp, rtol, atol);
+	CAPTURE("cos test");
+	trig_test(cos_decn, [](bmp::mpfr_float x) -> bmp::mpfr_float {return cos(x);}, rtol, atol);
 }
 
-static void atan_test(
-	const char* a_str, int a_exp, double rtol=5e-3, double atol=1e-3)
+static void cos_test(const char* a_str, int a_exp, double rtol=5e-3, double atol=1e-3)
 {
-	trig_test(arctan_decn, [](bmp::mpfr_float x) -> bmp::mpfr_float {return atan(x);}, a_str, a_exp, rtol, atol);
+	CAPTURE(a_str); CAPTURE(a_exp);
+	build_dec80(a_str, a_exp);
+	cos_test(rtol, atol);
 }
 
-static void asin_test(
-	const char* a_str, int a_exp, double rtol=5e-3, double atol=1e-3)
+
+static void tan_test(double rtol=5e-3, double atol=1e-3)
 {
-	trig_test(arcsin_decn, [](bmp::mpfr_float x) -> bmp::mpfr_float {return asin(x);}, a_str, a_exp, rtol, atol);
+	trig_test(tan_decn, [](bmp::mpfr_float x) -> bmp::mpfr_float {return tan(x);}, rtol, atol);
 }
 
-static void acos_test(
-	const char* a_str, int a_exp, double rtol=5e-3, double atol=1e-3)
+static void tan_test(const char* a_str, int a_exp, double rtol=5e-3, double atol=1e-3)
 {
-	trig_test(arccos_decn, [](bmp::mpfr_float x) -> bmp::mpfr_float {return acos(x);}, a_str, a_exp, rtol, atol);
+	CAPTURE(a_str); CAPTURE(a_exp);
+	build_dec80(a_str, a_exp);
+	tan_test(rtol, atol);
 }
 
 
+static void atan_test(double rtol=5e-3, double atol=1e-3)
+{
+	trig_test(arctan_decn, [](bmp::mpfr_float x) -> bmp::mpfr_float {return atan(x);}, rtol, atol);
+}
+
+static void atan_test(const char* a_str, int a_exp, double rtol=5e-3, double atol=1e-3)
+{
+	CAPTURE(a_str); CAPTURE(a_exp);
+	build_dec80(a_str, a_exp);
+	atan_test(rtol, atol);
+}
+
+
+static void asin_test(double rtol=5e-3, double atol=1e-3)
+{
+	trig_test(arcsin_decn, [](bmp::mpfr_float x) -> bmp::mpfr_float {return asin(x);}, rtol, atol);
+}
+
+static void asin_test(const char* a_str, int a_exp, double rtol=5e-3, double atol=1e-3)
+{
+	CAPTURE(a_str); CAPTURE(a_exp);
+	build_dec80(a_str, a_exp);
+	asin_test(rtol, atol);
+}
+
+
+static void acos_test(double rtol=5e-3, double atol=1e-3)
+{
+	trig_test(arccos_decn, [](bmp::mpfr_float x) -> bmp::mpfr_float {return acos(x);}, rtol, atol);
+}
+
+static void acos_test(const char* a_str, int a_exp, double rtol=5e-3, double atol=1e-3)
+{
+	CAPTURE(a_str); CAPTURE(a_exp);
+	build_dec80(a_str, a_exp);
+	acos_test(rtol, atol);
+}
+
 const char * const pi = "3.141592653589793239";
 const char * const pi_threequarters = "2.356194490192344929";
-const char * const pi_halfed = "1.570796326794896619";
-const char * const pi_quarted = ".7853981633974483096";
+const char * const pi_halved = "1.570796326794896619";
+const char * const pi_quarter = ".7853981633974483096";
 
 
 TEST_CASE("sin") {
@@ -96,8 +153,8 @@ TEST_CASE("sin") {
 	sin_test("2.5", 0);
 	sin_test("3.0", 0);
 	sin_test(pi, 0, -1);
-	sin_test(pi_quarted, 0);
-	sin_test(pi_halfed, 0);
+	sin_test(pi_quarter, 0);
+	sin_test(pi_halved, 0);
 	sin_test(pi_threequarters, 0);
 	sin_test("1000.0", 0);
 	sin_test("-0.5", 0);
@@ -129,8 +186,8 @@ TEST_CASE("cos") {
 	cos_test("2.5", 0);
 	cos_test("3.0", 0);
 	cos_test(pi, 0);
-	cos_test(pi_quarted, 0);
-	cos_test(pi_halfed, 0, -1);
+	cos_test(pi_quarter, 0);
+	cos_test(pi_halved, 0, -1);
 	cos_test(pi_threequarters, 0);
 	cos_test("1000.0", 0);
 	cos_test("-0.5", 0);
@@ -201,3 +258,122 @@ TEST_CASE("arccos") {
 	acos_test("0.9", 0);
 	acos_test("-0.9", 0);
 }
+
+
+static const int NUM_RAND_TRIG_TESTS = 4321; //trig tests are slow
+
+TEST_CASE("sin random"){
+	std::default_random_engine gen;
+	std::uniform_int_distribution<int> distrib(0,99);
+	std::uniform_int_distribution<int> exp_distrib(-1,0); //restrict range for now
+	std::uniform_int_distribution<int> sign_distrib(0,1);
+	for (int j = 0; j < NUM_RAND_TRIG_TESTS; j++){
+		for (int i = 0; i < DEC80_NUM_LSU; i++){
+			AccDecn.lsu[i] = distrib(gen);
+		}
+		int exp = exp_distrib(gen);
+		int sign = sign_distrib(gen);
+		set_exponent(&AccDecn, exp, sign);
+		int lsu0 = AccDecn.lsu[0];
+		CAPTURE(lsu0);
+		CAPTURE(exp);
+		CAPTURE(sign);
+		if (exp == -1 && lsu0 == 0){
+			//very small
+			sin_test(40);
+		} else if ((exp == -1 && lsu0 < 10) || (exp == 0 && lsu0 == 0)){
+			//small
+			sin_test(0.4);
+		} else if ((exp == 0 && lsu0 == 31)){
+			//near pi
+			sin_test(0.2);
+		} else if ((exp == 0 && lsu0 == 62)){
+			//near 2pi
+			sin_test(0.2);
+		} else if ((exp == 0 && lsu0 > 62)){
+			//large
+			sin_test(0.1);
+		} else {
+			sin_test(0.02);
+		}
+	}
+}
+
+TEST_CASE("cos random"){
+	std::default_random_engine gen;
+	std::uniform_int_distribution<int> distrib(0,99);
+	std::uniform_int_distribution<int> exp_distrib(-1,0); //restrict range for now
+	std::uniform_int_distribution<int> sign_distrib(0,1);
+	for (int j = 0; j < NUM_RAND_TRIG_TESTS; j++){
+		for (int i = 0; i < DEC80_NUM_LSU; i++){
+			AccDecn.lsu[i] = distrib(gen);
+		}
+		int exp = exp_distrib(gen);
+		int sign = sign_distrib(gen);
+		set_exponent(&AccDecn, exp, sign);
+		int lsu0 = AccDecn.lsu[0];
+		CAPTURE(lsu0);
+		CAPTURE(exp);
+		CAPTURE(sign);
+		if (exp == 0 && lsu0 == 15){
+			//near pi/2
+			cos_test(0.4);
+		} else if (exp == 0 && lsu0 == 47){
+			//near 3/2 * pi
+			cos_test(0.4);
+		} else if (exp == 0 && lsu0 == 78){
+			//near 5/2 * pi
+// 			cos_test(0.4);
+			cos_test(1.1); //actual rtol is much worse than 0.4, random test happens to hit a bad one
+		} else {
+			cos_test(0.02);
+		}
+	}
+}
+
+TEST_CASE("tan random"){
+	std::default_random_engine gen;
+	std::uniform_int_distribution<int> distrib(0,99);
+	std::uniform_int_distribution<int> exp_distrib(-1,0); //restrict range for now
+	std::uniform_int_distribution<int> sign_distrib(0,1);
+	for (int j = 0; j < NUM_RAND_TRIG_TESTS; j++){
+		for (int i = 0; i < DEC80_NUM_LSU; i++){
+			AccDecn.lsu[i] = distrib(gen);
+		}
+		int exp = exp_distrib(gen);
+		int sign = sign_distrib(gen);
+		set_exponent(&AccDecn, exp, sign);
+		int lsu0 = AccDecn.lsu[0];
+		CAPTURE(lsu0);
+		CAPTURE(exp);
+		CAPTURE(sign);
+		if (exp == -1 && lsu0 == 0){
+			//very small
+			tan_test(40);
+		} else if ((exp == -1 && lsu0 < 10) || (exp == 0 && lsu0 == 0)){
+			//small
+			tan_test(0.5);
+		} else if (exp == 0 && lsu0 == 15){
+			//near pi/2
+			tan_test(0.5);
+		} else if ((exp == 0 && lsu0 == 31)){
+			//near pi
+			tan_test(0.2);
+		} else if (exp == 0 && lsu0 == 47){
+			//near 3/2 * pi
+			tan_test(0.5);
+		} else if ((exp == 0 && lsu0 == 62)){
+			//near 2pi
+			tan_test(0.2);
+		} else if (exp == 0 && lsu0 == 78){
+			//near 5/2 * pi
+// 			tan_test(0.5);
+			tan_test(0.6); //actual rtol is much worse than 0.4, random test happens to hit a bad one
+		} else if ((exp == 0 && lsu0 > 62)){
+			//large
+			tan_test(0.1);
+		} else {
+			tan_test(0.02);
+		}
+	}
+}