Prove that cos(4x) = 8(cos^4(x))-8(cos^2(x)) + 1

cos(4x) = cos(2(2x)) = 2(cos^2(2x)) - 1 = 2 (cos^2(x) - 1)^2 - 1 = 8(cos^4(x)) - 8(cos^2(x)) + 1

HT
Answered by Harry T. Maths tutor

5541 Views

See similar Maths A Level tutors

Related Maths A Level answers

All answers ▸

The air pressure in the cabin of a passenger plane is modelled by the equation: P(x) = 3cos(x/2) - sin(x/2) where x is the altitude. Express P(x) in the form Rcos(x/2 +z) where z is acute and in degrees and then find the maximum pressure


What is the point of a derivative?


What is integration?


How do I check if events are independent (in statistics / probability)?


We're here to help

contact us iconContact ustelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

© MyTutorWeb Ltd 2013–2025

Terms & Conditions|Privacy Policy
Cookie Preferences