From the image and the problem written in Persian, you are asking to calculate the equivalent resistance of the circuit between points $A$ and $B$.

Circuit Details:

• There are three resistors:
  1. $R = 15 \, \Omega$
  2. $R = 11 \, \Omega$
  3. $R = 17 \, \Omega$
• Based on the diagram:
  • $R = 15 \, \Omega$ and $R = 11 \, \Omega$ are in parallel.
  • The equivalent resistance of the parallel combination is in series with $R = 17 \, \Omega$.

Steps to Solve:

Step 1: Parallel Combination

The formula for two resistors in parallel is: $R_{\text{parallel}} = \frac{R_1 \cdot R_2}{R_1 + R_2}$ Here: $R_{\text{parallel}} = \frac{15 \cdot 11}{15 + 11} = \frac{165}{26} \approx 6.35 \, \Omega$

Step 2: Total Resistance

The equivalent resistance $R_{\text{eq}}$ is the sum of $R_{\text{parallel}}$ and $R = 17 \, \Omega$: $R_{\text{eq}} = R_{\text{parallel}} + 17 = 6.35 + 17 = 23.35 \, \Omega$

Final Answer:

The equivalent resistance between points $A$ and $B$ is approximately: $R_{\text{eq}} \approx 23.35 \, \Omega$

Would you like more detailed steps or further clarification?

Related Questions:

1. What is the formula for calculating equivalent resistance in series and parallel circuits?
2. How does the total resistance change if more resistors are added in parallel?
3. What happens to the equivalent resistance if one of the resistors in parallel is removed?
4. Can you derive the formula for two resistors in parallel step-by-step?
5. What are practical examples of parallel and series resistor combinations in real circuits?

Tip: When combining resistors, always verify the configuration (series or parallel) carefully, as it affects the equivalent resistance significantly.