1. -e^(i Pi) 歐拉公式 (Euler's formula)
- (e ^ (i Pi)) = - ( COS(Pi) + iSin(Pi) ) = - ( COS (180) + i Sin(180) ) = - (-1) = 1
2. 1/Cos(60) = 1/(1/2) = 2 三角
3. 10 mod 7 = 10/7 ...3 餘數
4. Log2(16 ) , 2^4 = 16 , Log2(16) = 4 對數
5. S(3..2) 2Xdx = X^2 (3..2) = 3^2 - 2^2 = 9-4 = 5 定積分
6. 3! = 1 * 2 * 3 = 6 階層
7. |||2 , 111 base 2 => 1*2^2+1*2^1+1*2^0 = 4 + 2 + 1 = 7 以2為底的表示
8. Pi (i=0 .. 1) , (2i+2) (2*0+2) * (2*1+2) = 2*4 = 8 求積
∏是希臘字母,即π的大寫形式,在數學中表示求積運算, 類似於Σ 為求和.
9. Σ (i=1..3) (2i-1) = (2-1)+(4-1)+(6-1) = 1+3+5=9 , Σ 為求和運算
10. 5Csc (pi/6) = 5Csc (180/6 ) = 5(1/Sin(30)) = 5*(1/(1/2)) = 5*2 = 10 三角
11. gcf (33,110) => 33 = 11*3 , 110 = 11*10 , GCF = 11 (highest common factor 最大公因數)
12. 4P2 , P => Permutation 排列, 4 個物體中 任兩個一組的 排列個數
nPm = n!/m! , 4P2 = 4!/2!=12. 小時後上課時是用 P 的 4 取 2 來表示