The point \( (3, -4) \) lies on both the circles \( x^{2} + y^{2} - 2x + 8y + 13 = 0 \) and \( x^{2} + y^{2} - 4x + 6y + 11 = 0 \). Then, the angle between the circles is
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Use $\cos \theta = \frac{d^{2}-r_{1}^{2}-r_{2}^{2}}{2r_{1}r_{2}}$ to find the angle between two intersecting circles.