We begin by stating the given information:
`F (x) = f(x^9)` ... Eq. 1.1
`G(x) = (f(x))^9` ... Eq. 1.2
Additionally we are given :
`a^8 = 6` ... Eq. 2.1
`f(a) = 2` ... Eq. 2.2
`f'(a) = 12` ... Eq. 2.3
`f'(a^9) = 4` ... Eq. 2.4
We are required to find:
`F'(a) = ?`
And
We have to use to above equation to solve what is required. Let's begin by solving F'(a):
If `F(x) = f(x^9)`
` `
Then using the chain rule :
`F'(x) = f'(x^9) * 9x^8`
Therefore applying ourselves, by substituting 'a' for 'x':
`F' (a) = f'(a^9) * 9a^8`
We can now substitute Eq. 2.4 and Eq. 2.1
`F'(a) = 4 * 9(6) = 216`
We have solved the first part, now let's solve the last part:
If `G(x) = (f(x))^9`
Then using the chain rule:
`G'(x) = 9[f(x)}^8 * f'(x)`
Now we can apply ourselves by substituting 'a' for 'x':
`G'(a) = 9 [f(a)]^8 * f'(a)`
Now substitute eq. 2.2 and eq. 2.3 in the above equation:
`G'(a) = 9* (2)^8 * 12 = 27648`
SUMMARY:
F'(a) = 216
G'(a) = 27648
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