  function purchasePrice(
    SD59x18 _amount,
    SD59x18 _emissionRate,
    SD59x18 _k,
    SD59x18 _decayConstant,
    SD59x18 _timeSinceLastAuctionStart
  ) internal pure returns (SD59x18) {
    if (_amount.unwrap() == 0) {
      return SD59x18.wrap(0);
    }
    SD59x18 topE = _decayConstant.mul(_amount).div(_emissionRate);
    topE = topE.exp().sub(ONE);
    SD59x18 bottomE = _decayConstant.mul(_timeSinceLastAuctionStart);
    bottomE = bottomE.exp();
    SD59x18 result;
    if (_emissionRate.unwrap() > 1e18) {
      result = _k.div(_emissionRate).mul(topE).div(bottomE);
    } else {
      result = _k.mul(topE.div(_emissionRate.mul(bottomE)));
    }
    return result;
  }
  function purchaseAmount(
    SD59x18 _price,
    SD59x18 _emissionRate,
    SD59x18 _k,
    SD59x18 _decayConstant,
    SD59x18 _timeSinceLastAuctionStart
  ) internal pure returns (SD59x18) {
    if (_price.unwrap() == 0) {
      return SD59x18.wrap(0);
    }
    SD59x18 exp = _decayConstant.mul(_timeSinceLastAuctionStart).exp();
    SD59x18 lnParam = _k.add(_price.mul(_emissionRate).mul(exp)).div(_k);
    SD59x18 numerator = _emissionRate.mul(lnParam.ln());
    SD59x18 amount = numerator.div(_decayConstant);
    return amount;
  }
diff --git a/src/libraries/ContinuousGDA.sol b/src/libraries/ContinuousGDA.sol
index 721d626..7e2bb61 100644
--- a/src/libraries/ContinuousGDA.sol
+++ b/src/libraries/ContinuousGDA.sol
@@ -36,9 +36,9 @@ library ContinuousGDA {
     bottomE = bottomE.exp();
     SD59x18 result;
     if (_emissionRate.unwrap() > 1e18) {
-      result = _k.div(_emissionRate).mul(topE).div(bottomE);
+      result = _k.div(_decayConstant).mul(topE).div(bottomE);
     } else {
-      result = _k.mul(topE.div(_emissionRate.mul(bottomE)));
+      result = _k.mul(topE.div(_decayConstant.mul(bottomE)));
     }
     return result;
   }
@@ -62,7 +62,7 @@ library ContinuousGDA {
       return SD59x18.wrap(0);
     }
     SD59x18 exp = _decayConstant.mul(_timeSinceLastAuctionStart).exp();
-    SD59x18 lnParam = _k.add(_price.mul(_emissionRate).mul(exp)).div(_k);
+    SD59x18 lnParam = ONE.add(_price.mul(_decayConstant).mul(exp)).div(_k);
     SD59x18 numerator = _emissionRate.mul(lnParam.ln());
     SD59x18 amount = numerator.div(_decayConstant);
     return amount;
@@ -83,7 +83,7 @@ library ContinuousGDA {
   ) internal pure returns (SD59x18) {
     SD59x18 exponent = _decayConstant.mul(_targetFirstSaleTime);
     SD59x18 eValue = exponent.exp();
-    SD59x18 multiplier = _emissionRate.mul(_price);
+    SD59x18 multiplier = _decayConstant.mul(_price);
     SD59x18 denominator = (_decayConstant.mul(_purchaseAmount).div(_emissionRate)).exp().sub(ONE);
     SD59x18 result = eValue.div(denominator);
     return result.mul(multiplier);
