Skip to content

Course home

Sign up

Exponentials and Logarithms

EasyMediumHard
123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158
Question 44
a.

Using y=2xy = 2^xy=2x as a substitution, show that 4x−2x+1−2=04^x - 2^{x+1} - 2 = 04x−2x+1−2=0 can be written as y2−2y−2=0y^2 - 2y - 2 = 0y2−2y−2=0.

[2]
b.

Hence, show that the equation 4x−2x+1−2=04^x - 2^{x+1} - 2 = 04x−2x+1−2=0 has x=log⁡2(1+3)x = \log_2(1+\sqrt{3})x=log2​(1+3​) as its only solution.

[4]
Markscheme

Exponentials and Logarithms Questions

  1. A Level
  2. /Maths
  3. /Exponentials and Logarithms

277 exam-style questions on Edexcel A Level Maths Exponentials and Logarithms, covering 14.1 Exponential Functions, 14.2 y = e^x, 14.3 Exponential Modelling, 14.4 Logarithms, 14.5 Laws of Logarithms, 14.6 Solving Equations using Logarithms, 14.7 Working with Natural Logarithms, and 14.8 Logarithms and Non-Linear Data. Each one has a worked solution and a mark scheme showing where the marks go.

Question bank