73 M1 2 M1 for method of finding inverse H f(x) = 3 7x – Find f–1(x) from = 3 7x: y – y 7x = 3 – = x So f–1(x) = A1 A1 cao y Find g–1(x) from = 7x + 3: y 7x = 3 – M1 M1 for method of finding inverse x = So g-1(x) = So f-1(x) + g-1(x) = + = = A1 A1 cao = 0 as required. P1 P1 for showing how the two functions can be added together C1 C1 for complete explanation of how they sum to 0 6
73 f(x) = 3 – 7x Find f–1(x) from y = 3 – 7x: 7x = 3 – y x = So f–1(x) = Find g–1(x) from y = 7x + 3: 7x = y – 3 x = So g-1(x) = So f-1(x) + g-1(x) = + = = = 0 as required. M1 A1 M1 A1 P1 C1 2 M1 for method of finding inverse A1 cao M1 for method of finding inverse A1 cao P1 for showing how the two functions can be added together C1 for complete explanation of how they sum to 0 H 6
Higher_Skills_Algebra_MarkScheme_Edexcel.docx