vecA and vecB are vectors such that A +BI= I A -B j. Then, the angle between them is

Explanation

To solve the problem where vectors \( \vec{A} \) and \( \vec{B} \) are given by the equations \( A + Bi = I A - Bj \), we need to find the angle between these two vectors.

### Step-by-Step Solution:

1. **Identify the Components of the Vectors**:
From the equation \( A + Bi = I A - Bj \), we can separate the real and imaginary parts.
- The left side \( A + Bi \) can be interpreted as \( \vec{A} = A \hat{i} + B \hat{j} \).
- The right side \( I A - B j \) can be interpreted as \( \vec{B} = A \hat{i} - B \hat{j} \).
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