Question

If $k \int_{0}^{1} x f(3x) dx = \int_{0}^{3} t f(t) dt$ then $k =$

• A. 9
• B. 3
• C. 1/9
• D. 1/3

Hint:

When replacing $x$ with $ax$ in the argument, the factor outside the integral often involves $a^2$ if there is an additional $x$ term.

Answer 1

The Correct Option is A