The following is a technical analysis framework for cryptocurrency contract long position investment strategies, combining the comprehensive use of trend indicators (EMA) and auxiliary indicators (MACD, RSI):

1. Core Trend Analysis: EMA (Exponential Moving Average)

EMA is the core tool for trend tracking, characterized by giving more weight to recent prices, allowing for a quick response to short-term trend changes.

1. Parameter Settings

- Short-term EMA: 7-period (to capture short-term momentum)

- Long-term EMA: 30-period (to assess medium-term trend)

- Alternative Parameters: 5/20, 12/50 (adjust according to trading frequency)

2. Long Position Entry Signals

- Golden Cross Confirmation: EMA7 crosses above EMA30, and price stabilizes above EMA30.

- Slope Verification: EMA30 is tilted upwards, avoiding false breakouts during sideways periods.

- Price Pullback: In an upward trend, price pulls back to near EMA30 and rebounds (point for adding positions in the direction of the trend).

3. Trend Strength Assessment

- Bullish Divergence: The distance between EMA7 and EMA30 expands, and price moves up along EMA7.

- Bearish Alert: Price breaks below EMA7 and approaches EMA30, requiring vigilance against trend weakening.

2. Momentum Verification: MACD (Moving Average Convergence Divergence)

MACD assists in assessing trend momentum and potential reversals, reducing the impact of EMA lag.

1. Key Signals

- Double Line Golden Cross: MACD line (DIF) crosses above the signal line (DEA), reinforcing bullish signals in conjunction with EMA golden cross.

- Histogram Turns Positive: Green bars (positive values) expand, indicating increased upward momentum.

- Zero Axis Breakthrough: MACD double lines rise from below the zero axis to above, confirming trend reversal.

2. Divergence Warning

- Top Divergence: Price makes a new high, but MACD peaks decline, indicating a potential exhaustion of upward momentum (signal to reduce positions).

- Bottom Divergence: Price makes a new low but MACD low points rise, indicating a potential reversal signal (to be filtered with EMA).

3. Overbought/Oversold Assistance: RSI (Relative Strength Index)

RSI measures the market's short-term overbought and oversold conditions, avoiding chasing highs and cutting losses.

1. Parameter Settings

- Period: 14 (to balance sensitivity and stability)

- Overbought/Oversold Thresholds: 70/30 (can be adjusted to 80/20 for the cryptocurrency market to adapt to high volatility)

2. Combining Long Position Strategies

- Trend Following: In a bullish EMA trend, RSI > 50 maintains a bullish outlook; brief overbought (RSI > 70) does not rush to take profit.

- Pullback Opportunity: EMA trend remains intact, RSI falls back to around 50 and rebounds, considered a secondary entry point.

- Divergence Alert: Price makes a new high but RSI does not, combined with MACD divergence, requires vigilance against reversal.

4. Long Position Strategy Integration

1. Entry Conditions

- Necessary Condition: EMA7 > EMA30, and price stabilizes above EMA30.

- Enhanced Signal: MACD golden cross and histogram expansion, RSI > 50.

- Filtering Conditions: Avoid chasing highs when RSI > 80 and price is far from EMA.

2. Exit Strategy

- Take Profit: Take profit in batches (e.g., 50% of the position exits when RSI > 80, remaining position follows EMA7).

- Stop Loss: 2%-3% below EMA30 (or combined with ATR for dynamic stop loss).

- Trend End Signal: EMA death cross (EMA7 crossing below EMA30) or MACD death cross + RSI breaking below 50.

5. Risk Control and Precautions

1. Volatility Risk: The cryptocurrency market is highly volatile, requiring position size reduction (recommended single trade risk <2% of capital).

2. Limitations of Indicators:

- EMA lag can easily generate false signals in a range market, requiring the combination of price structure (such as support/resistance).

- MACD/RSI may remain overbought in a one-sided market, avoiding premature counter-trend operations.

3. Market Environment Adaptation:

- Trending Market: EMA + MACD as primary, RSI as auxiliary.

- Range Market: Reduce trading frequency, waiting for breakout signals after EMA flattens.

6. Practical Case Studies (BTC/USDT)

1. Trend Initiation: BTC breaks above EMA30, EMA7 crosses above EMA30 forming a golden cross.

2. Momentum Verification: MACD golden cross and the histogram continues to expand, RSI rebounds above 60.

3. Entry Point: Price pulls back to EMA30 and rebounds, with a stop loss set 3% below EMA30.

4. Exit: MACD top divergence + RSI > 85, take profit in batches; final EMA death cross confirms trend reversal.

Summary: EMA is the core trend filter, MACD verifies momentum strength, and RSI aids in timing decisions. These three need to be used in conjunction, along with price behavior and risk management, to avoid reliance on a single indicator. It is recommended to backtest historical data to optimize parameters and to pay attention to on-chain data, market sentiment, and other non-technical factors to enhance win rates.