Given f(x)=x*2+8 and g(x)= (x+4)/x, find (g*f)(-4)?
回答 (2)
2014-01-16 2:58 pm
✔ 最佳答案
(g*f)(-4) = (x + 4)/x * x^2 + 8....(x + 4)(x^2 + 8)
=-------------------------
............x
....(- 4 + 4)[(-4)^2 + 8]
=--------------------------------
.......... - 4
.....0(24)
= ----------
......- 4
= 0 answer//
2014-01-16 10:47 pm
Well,
i hope x*2 means x^2 (so the square : x^2 is the "correct" notation here)
and (g*f should be gof (the composition...)
so
f(x)=x*2+8 and g(x)= (x+4)/x
(g o f)(-4) = g( f(-4) ) = g( (-4^2 + 8) = g(24) = (24 + 4)/24 = 28/24 = 7/6
finally
(gof)(-4) = 7/6
et voilà !
Bonne Année from France !
hope it' ll help !!
i hope x*2 means x^2 (so the square : x^2 is the "correct" notation here)
and (g*f should be gof (the composition...)
so
f(x)=x*2+8 and g(x)= (x+4)/x
(g o f)(-4) = g( f(-4) ) = g( (-4^2 + 8) = g(24) = (24 + 4)/24 = 28/24 = 7/6
finally
(gof)(-4) = 7/6
et voilà !
Bonne Année from France !
hope it' ll help !!
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