Hello, notadummy!
Exactly where is your difficulty?
. . The product rule?
. . The chain rule?
. . Basic algebra?
The most likely scenario: The book has a totally <u>simplified</u> answer
. . and you want to know how they did it.
Find the derivative: .\(\displaystyle g(t)\:=\:t^3(t^4\,+\,5)^{\frac{7}{2}}\)
Differentiate:
.\(\displaystyle g'(x)\:=\:t^3\cdot\frac{7}{2}(t^4\,+\,5)^{\frac{5}{2}}\cdot4t^3\:+\:3t^2\cdot(t^4\,+\,5)^{\frac{7}{2}}\)
. . . . \(\displaystyle =\;14t^6(t^4\,+\,5)^{\frac{5}{2}}\:+\:3t^2(t^4\,+\,5)^{\frac{7}{2}}\)
Factor:
.\(\displaystyle t^2\cdot(t^4\,+\,5)^{\frac{5}{2}}\cdot[14t^4\,+\,3(t^4\,+\,5)]\)
. . . . \(\displaystyle =\;t^2\cdot(t^4\,+\,5)^{\frac{5}{2}}\cdot[14t^4\,+\,3t^4\,+\,15]\)
. . . . \(\displaystyle =\;t^2\cdot(t^4\,+\,5)^{\frac{5}{2}}\cdot(17t^4\,+\,15)\)