<p>hi,</p>
<p>Given f(x)=2/x+4 and g(x)=x^2-2, find each function…
(f+g)(x)</p>
<p>Do I add them together?</p>
<p>and…</p>
<p>Find <a href=“x”>f * g</a> and <a href=“x”>g * f</a>, when</p>
<p>f(x)=1/3x+5 and g(x)=x-3</p>
<p>Thanks in advance, I need to understand functions better…</p>
<p>Yes, it just means to either add or multiply depending on what is being asked.
Just think of it as having two expressions and deciding whether to subtract, or add or whatever the case may be. hope this helps</p>
<p>For the first one yes just add
and the second one just multiply.</p>
<p>how could u do it, for the first one, with the 2 on top?</p>
<p>I understand the second one now</p>
<p>Mactonycw:
Assuming f(x) is 2/(x+4) and not (2/x) + 4, then</p>
<p>(f+g)(x) = (2/(x+4)) + (x^2 - 2)
= (2 + (x+4)(x^2 - 2)) / (x+4)
= (2 + x^3 + 4x^2 -2x -8) / (x+4)
= (x^3 + 4x^2 - 2x -6) / ( x + 4)</p>
<p>ok, I’m going to guess where to put in the parentheses, so here goes…</p>
<p>For the first one…
if f(x) = 2/(x+4) and g(x) = x^(2)-2, then:
(f+g)(x)=f(x) + g(x)= 2/(x+4) + (x^(2)-2)= 2/x + 1/2 + x^2 - 2=x^2+2/x-3/2</p>
<p>And the second…
if f(x) = 1/(3x+5) and g(x) = x-3, then:
(f * g)(x) = f(g(x)) = f(x-3) = 1/(3(x-3)+5) = 1/(3x-4)
and:
(g * f)(x) = g(f(x)) = g(1/(3x+5)) = 1/(3x+5) - 3 = 1/3x - 14/5</p>
<p>I hope my parentheses were right. haha hope it at least helps.</p>
<p>CornerStones:
Careful! 2 / (x+4) is <em>not</em> the same as 2/x + 1/2 .</p>
<p>haah right on ok I shall redo! yikes… so much for 800 math</p>