Let $\phi(\text{x})=\text{f}(\text{x})+\text{f}(2\text{a}-\text{x})$ and f'(x) > 0 for all $\text{x}\in[0,\text{a}].$ Then, $\phi(\text{x}):$
View full solution →- Increases on [0, a]
- Decreases on [0, a]
- Increases on [-a, 0]
- Decreases on [a, 2a]