| 73 | 73th LS(210714) Ch9.4 Mathematical Induction (PDF P679) | Jp Park  | 2021-07-15 | 1 |
| 72 | 72th LS(210625) Ch9.2 Arithmetic Sequence (PDF P654) | Jp Park | 2021-06-26 | 1 |
| 71 | 71th LS(210618) Ch8.4 Determinant of Square Matrix (PDF P608.. | Jp Park | 2021-06-19 | 1 |
| 70 | 70th LS(210611) Ch8.1 Matrix and System Eqs (PDF P573) | Jp Park | 2021-06-12 | 2 |
| 69 | 69th LS(210601) Ch7.5 Systems of inequalities (PDF P542) | Jp Park | 2021-06-02 | 0 |
| 68 | 68th LS(210518) Ch7.2 Two Variables Linear System (PDF P516) | Jp Park | 2021-05-19 | 4 |
| 67 | 67th LS(210511) Ch6.5 Trigonometric form of a Complex Number.. | Jp Park | 2021-05-12 | 1 |
| 66 | 66th LS(210504) Ch6.3 Vector(PDF P458) | Jp Park | 2021-05-05 | 2 |
| 65 | 65th LS(210420) Ch6.1 Sine Law (PDF P436) | Jp Park | 2021-04-21 | 1 |
| 64 | 64th LS(210415) Ch5.4 Sum and Difference (PDF P399) | Jp Park | 2021-04-16 | 1 |
| 63 | 63th LS(210323) Ch5.2 Verifying Trigonometric Identities(PD.. | Jp Park | 2021-03-24 | 13 |
| 62 | 62th LS(210316) Ch4.6 Graph of other Trigometric Functions(.. | Jp Park | 2021-03-17 | 11 |
| 61 | 61th LS(210309) Ch4.2 Trigomo,etric Functions(PDF P295) | Jp Park | 2021-03-10 | 5 |
| 60 | 60th LS(210302) Ch3 Exponetial and Log Functions(PDF P256) | Jp Park | 2021-03-03 | 11 |
| 59 | 59th LS(210223) Ch2.7 Rational Functions(PDF P200) | Jp Park | 2021-02-24 | 5 |
| 58 | 58th LS(210218) Ch2.5 Zero of Polynomial Functions(PDF P171.. | Jp Park | 2021-02-19 | 2 |
| 57 | 57th LS(210209) Ch2.2 Polynomial Functions of Higher Degree(.. | Jp Park | 2021-02-10 | 1 |
| 56 | 56th LS(210202) Ch1.9 Inverse Functions(PDF P96) | Jp Park | 2021-02-03 | 1 |
| 55 | 55th LS(210126) Ch1.4 Functions(PDF P53) | Jp Park | 2021-01-27 | 1 |
| 54 | 54th LS(210119) Ch11 끝까지 | Jp Park | 2021-01-20 | 1 |
