## anonymous one year ago check my answer please. Suppose that the functions p and q are defined as follows. p(x)=x^2+3 q(x)=sqrt(x+2) find (q*p)(2)=[?] and (p*q)(2)=[?] I got (q*p)(2)=sqrt 10 and (p*q)(2)=8

1. anonymous

$p(x)=x^2+3$$q(x)=\sqrt{x+2}$ $(qp)(x)=q(x) \times p(x)$ $pq(x)=p(x) \times q(x)$ Since multiplication is commutative, I don't understand how you are getting different answers

2. UsukiDoll

this could be a composite function question like (q o p) (x) or (p o q)(x) ?

3. anonymous

4. anonymous

sorry yes (q o p) (x) or (p o q)(x) i the right format

5. anonymous

6. anonymous

well I followed the steps shown in my book, can you explain then

7. anonymous

Can you show me your steps, how you've attempted the question?

8. anonymous

(q o p) q(p(2)) q(2^2+3) q(7) sqrt 7+3= sqrt 10 (p o q) p(q(2)) p(sqrt 2+3) p(sqrt 5) (sqrt 5)^2+3=8

9. anonymous

I see the mistake now, let me ask you first what is your q(x)? $q(x)=\sqrt{x+2}$ $q(x)=\sqrt{x+3}$ Because in the question you've said sqrt{x+2} but in the solution you've used sqrt{x+3}

10. anonymous

ahh I made a silly mistake! thanks for catching it!

11. anonymous

You're welcome, your method of doing the question is perfectly fine, which is good as that means you've grasped the concept, only thing is you made a calculation mistake, that's not a big problem you just have to be careful