期货价格

def solve(spot_price, risk_free_rate, time_to_maturity, storage_cost, convenience_yield):
    import math
    futures_price = spot_price * math.exp((risk_free_rate + storage_cost - convenience_yield) * time_to_maturity)
    return {"现货价格": spot_price, "无风险利率": risk_free_rate, "期货价格": round(futures_price, 2)}