# Exponential Curve

A exponential curve performs a multiplicative operation where the delta acts as a multiplier function. If the pool has just sold an NFT by giving out an NFT and receiving tokens, the next price it will quote to sell NFTs at will increase by a percentage amount (known as **delta**).

1. The price of the NFT increased by a percentage each time an item is bought from the pool. The reverse happens when an item is sold into the pool.
2. `delta` is a percentage and assumes that the starting price is 100%. If input the `delta` as 20% it means we want the price to increase/decrease by 20% after each trade. For example, initial price is `1Ξ`, after someone buys 1 NFT from the pool, the next price will increase by the delta to `1.2Ξ`, conversely, if someone sells 1 NFT tot he pool, the next price will decrease by a multiple of the delta to `0.8333Ξ`
3. The delta is a percentage, and assumes that 100% (meaning no change to price after a buy/sell operation) is `1e18`. If we want the price to increase/decrease by 20% on each buy/sell, we should input `1.2e18` to represent `120% = (100% + 20%)`. The initial price is `1.0`. After someone buys 1 NFT from the pool, the price will be `1.2 = 1.0 * 120%`. If someone sells an NFT into the pool, the price will be `0.8333 = 1.0 / 120%`.