Show that cosh(x+y) = cosh(x)cosh(y) + sinh(x)sinh(y)

RHS: cosh(x)cosh(y) + sinh(x)sinh(y) = 1/4(e^x + e^-x)(e^y + e^-y) + 1/4(e^x - e^-x)(e^y - e^-y) = 1/4(e^x.e^y + e^x.e^-y + e^-x.e^y + e^-x.e^-y + e^x.e^y - e^x.e^-y - e^-x.e^y + e^-x.e^-y) = 1/4(2e^x.e^y + 2e^-x.e^-y) = 1/2(e^x.e^y + e^-x.e^-y) = 1/2(e^(x+y) + e^-(x+y)) = cosh(x+y) [QED]

Answered by Alex H. Maths tutor

5443 Views

See similar Maths A Level tutors

Related Maths A Level answers

All answers ▸

whats the integral of x.e^x wrt x


x^3 + 3x^2 + 2x + 12


Find dy/dx of y = a^x


if f(x) = 7x-1 and g(x) = 4/(x-2), solve fg(x) = x


We're here to help

contact us iconContact usWhatsapp logoMessage us on Whatsapptelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

© MyTutorWeb Ltd 2013–2025

Terms & Conditions|Privacy Policy
Cookie Preferences