Show that sin2A is equal to 2sinAcosA

This question requires you to use the trigonometric identity sin(A+B)=sinAcosB + sinBcosA. The difficulty in this problem is noticing that you need to substitute 2A for A+A and then you can simply put this into the trig identity. Doing this leads to you sin2A=sinAcosA + sinAcosA which is 2sinAcosA.

SL
Answered by Samuel L. Maths tutor

36951 Views

See similar Maths A Level tutors

Related Maths A Level answers

All answers ▸

Find the stationary points of y= 5x^2 + 2x + 7


Express asin(x) + bcos(x) in the form Rsin(x+c), where c is a non-zero constant.


Given f(x): 2x^4 + ax^3 - 6x^2 + 10x - 84, and knowing 3 is a root of f(x), which is the value of a?


I've been told that I can't, in general, differentiate functions involving absolute values (e.g. f(x) = |x|). Why is that?


We're here to help

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

MyTutor is part of the IXL family of brands:

© 2026 by IXL Learning