Final answer:
To find tan(a - b), substitute the values of tan(a) and tan(b) into the formula: tan(a - b) = (tan(a) - tan(b)) / (1 + tan(a) * tan(b)). Hence, tan(a - b) = 0.
Step-by-step explanation:
To find tan(a - b), we can use the formula for the tangent of the difference of two angles: tan(a - b) = (tan(a) - tan(b)) / (1 + tan(a) * tan(b)). From the given information, we know that tan(a) = 4 and tan(b) = 4. Substituting these values into the formula, we get tan(a - b) = (4 - 4) / (1 + 4 * 4) = 0 / 17 = 0.