# Toronto Math Forum

## APM346--2020S => Quizzes and Tests => Test 1 => Topic started by: Yan Zhou on February 21, 2020, 12:18:28 PM

Title: past test 2019 day problem 3B
Post by: Yan Zhou on February 21, 2020, 12:18:28 PM
I think there are some typo in the answer of u(x,t).
$$u(x,t) = 6sin(x+3t) + 6sin(x-3t)$$ as $x>3t$,
$$u(x,t) = 6sin(x+3t) + 6sin(2(x-3t))$$ as $t<x<3t$.