i submit what you gave for problem 3 and this is what is showing

Tests: 4 of 6 Tests Passed (60%) e @ not provided class function 0% (0%) mean value of filtered function correct 0% (5%) Variable a0 has an incorrect value. function output yf is not of the same size as function input t @ filtered signal with frequencies fmax correct 20% (20%) @ filtered signal with frequencies in band 20% (20%) result correct 0% (35%) Variable yf has an incorrect value