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**1. Homework Statement**

Two long straight wires sit at the lower corners of an equilateral triangle and carry current I. Find the magnitude and direction of the B field at the top vertex of the triangle for the case where:

a) the current in both lower wires flows out of the page

b) the current in the left wire flows out of the page, the current of the right wire flows into the page.

**2. Homework Equations**

dB=(μ_o Idlsinθ)/(4πr^2 ) for the magnetic field at a point P in space

**3. The Attempt at a Solution**

First, I don't really know what effect being physically connected to the current-bearing wires has on P. Assuming it's negligible, though, then working with just one wire

r= length of triangle side from P to current-bearing wire

R= distance directly from P to the wire?

B= (u_o*I/4π) integral[dlsinθ/r^2]

dl= R(csc^2θdθ = r^2dθ/R

B= (u_o*I/4πR) [int from θ=0 to π] sinθdθ = -(u_o*I/4πR)cosθ evaluated from 0 to π

This is based mostly around an example for another problem, but I think most of it applies... However I am confused on the integral boundaries (if it's an equilateral triangle, shouldn't θ be fixed at 60?) and am unsure how how incorporate the second wire. Help, please!