- #1
frosty8688
- 126
- 0
1. Find the intervals of increase and decrease
2. [itex] C(x)=x^{1/3}(x+4) [/itex]
3. [itex] C(x)=x^{4/3}+4x^{1/3}; C'(x)=\frac{4}{3}x^{1/3}+\frac{4}{3}x^{-2/3}=\frac{4x^{1/3}}{3}+\frac{4}{3x^{2/3}}=\frac{x^{2/3}}{x^{2/3}}*\frac{4x^{1/3}}{3}+\frac{4}{3x^{2/3}}=\frac{4x+4}{3x^{2/3}}[/itex] I am wondering why the only critical number is -1, when 0 should also be considered.
2. [itex] C(x)=x^{1/3}(x+4) [/itex]
3. [itex] C(x)=x^{4/3}+4x^{1/3}; C'(x)=\frac{4}{3}x^{1/3}+\frac{4}{3}x^{-2/3}=\frac{4x^{1/3}}{3}+\frac{4}{3x^{2/3}}=\frac{x^{2/3}}{x^{2/3}}*\frac{4x^{1/3}}{3}+\frac{4}{3x^{2/3}}=\frac{4x+4}{3x^{2/3}}[/itex] I am wondering why the only critical number is -1, when 0 should also be considered.