SOLUTION: Combining functions with (f*g)(x) and (f*g)(4): f(x)= sqrt(4x-1) g(x)=x^2-10 I've tried sqrt(4x^2-1-10) But, I didn't know how I would multiply that by 4, so it doesn't seem r

Algebra ->  Functions -> SOLUTION: Combining functions with (f*g)(x) and (f*g)(4): f(x)= sqrt(4x-1) g(x)=x^2-10 I've tried sqrt(4x^2-1-10) But, I didn't know how I would multiply that by 4, so it doesn't seem r      Log On


   

Question 1006791: Combining functions with (f*g)(x) and (f*g)(4):
f(x)= sqrt(4x-1) g(x)=x^2-10
I've tried sqrt(4x^2-1-10)
But, I didn't know how I would multiply that by 4, so it doesn't seem right.
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
I'm assuming when you write (f*g)(x), you really mean "f times g of x" and it is NOT function composition. If it is function composition, then please let me know.


f%28x%29+=+sqrt%284x-1%29


f%284%29+=+sqrt%284%2A4-1%29 Replace every x with 4.


f%284%29+=+sqrt%2816-1%29


f%284%29+=+sqrt%2815%29


----------------------------


g%28x%29+=+x%5E2-10


g%284%29+=+4%5E2-10 Replace every x with 4


g%284%29+=+16-10


g%284%29+=+6


----------------------------


%28f%2Ag%29%28x%29+=+f%28x%29%2Ag%28x%29


%28f%2Ag%29%284%29+=+f%284%29%2Ag%284%29 Replace every x with 4


%28f%2Ag%29%284%29+=+f%284%29%2Ag%284%29 Replace f%284%29 with sqrt%2815%29


%28f%2Ag%29%284%29+=+sqrt%2815%29%2A6 Replace g%284%29 with 6


%28f%2Ag%29%284%29+=+6%2Asqrt%2815%29 Exact value


%28f%2Ag%29%284%29+=+23.2379000772446 Approximate value (use a calculator)