A signal processor's response function R(x)R(x)R(x) is defined by the expansion of R(x)=(2x−5)8R(x) = (2x - 5)^8R(x)=(2x−5)8.
Show that the first three terms, in descending powers of xxx, of this expansion are given by 256x8+ax7+bx6256x^8 + ax^7 + bx^6256x8+ax7+bx6 where aaa and bbb are integers to be found.
Find the constant term in the expansion of (2x−5x)8\left(2x - \frac{5}{x}\right)^8(2x−x5)8
Practise Edexcel A Level Maths 4.2 Expanding (a + bx)^n with exam-style questions for A Level Maths. 99 questions, matched to the Edexcel A Level Maths (9MA0) specification and written in Paper 1, Paper 2 and Paper 3 style. Every question includes a full worked solution and mark scheme, so you can see where marks are awarded rather than just whether you got the answer right.