Question 450947
{{{(1/a^2 + 1/b^2)/(1/a + 1/b) = ((a^2 + b^2)/(a^2b^2))/((a+b)/(ab))

= ((a^2 + b^2)/(ab))/(a+b)
= (a^2 + b^2)/((ab)(a+b))

}}}