Prove: (1-cos(2A))/sin(2A) = tan(A)

Firstly we must lay out our double angle formulas which are required for this question: cos(2A) = 1-2sin^2(A) = 2cos^2(A)-1 sin(2A) = 2sin(A)cos(A) Working from LHS: (1-cos(2A))/sin(2A) Focusing on the denominator 1-cos(2A) = 1-(1-2sin^2(A)) = 2sin^2(A) Focusing on the numerator sin(2A) = 2sin(A)cos(A) Therefore, overall: (1-cos(2A))/sin(2A) = 2sin^2(A)/2sin(A)cos(A) = 2*sin(A)sin(A) / 2sin(A)*cos(A) = sin(A)/cos(A) = tan(A) AS REQUIRED 

Answered by Rishi P. Maths tutor

18895 Views

See similar Maths A Level tutors

Related Maths A Level answers

All answers ▸

F ind all values of x in the range 0° <= x <= 180° satisfying tan(x+45°)= 8tan(x)


Using the identity cos(A+B)= cosAcosB-sinAsinB, prove that cos2A=1-2sin^2A.


Prove that 8 times any triangle number is always 1 less than a square number


A curve C is mapped by the equation ( 1+x)(4-x). The curve intersects the x-axis at x = –1 and x = 4. A region R is bounded by C and the x-axis. Use calculus to find the exact area of R.


We're here to help

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