| Example If 4 £ x £ 8 and 3 £ y £ 5 find the minimum value of Solution : Minimum value of y is 3 Maximum value of x is 8 Therefore, minimum value of Example Solve i) Solution : i) For any value of x, x2 ³ 0 Þ x2 + 5 > 0 Multiplying by x2 + 5 to each side x - 3 £ 2 . . . [ if a < b, c > 0 then a c < b c] x £ 5 ii) For any value of x, x2 ³ 0 Þ x2 + 5 > 0 Multiplying by x2 + 2 to each side 3x2 + x < 3x2 + 6 . . . [ if a < b, c > 0 then a c < b c ] 3x2 + x - 3x2 + < 3x2 + 6 - 3x2 . . . [if a < b then a - c < b - c] x < 6
|
7.1 Definition |
ii)
justify each step.