Differentiante y = arctan(c)

y = arctan(x)tan(y) = xsec²(y) = dx/dyfrom cos²A + sin²A = 1, we know that 1 + tan²A = sec²A (divide by cos²A), so we substitute in1 + tan²(y) = dx/dyfrom the initial relationship,1 + x² = dx/dyfinally reciprocate the expression to get1/(1+x²) = dy/dx (Solved)