Express 3 cos θ + 4 sin θ in the form R cos(θ – α), where R and α are constants, R > 0 and 0 < α < 90°.

To find the value of R, use Pythagoras's Theorem using the coeffecients of cos θ and sin θ. The correct answer should be R=5. Expand the expression  R cos(θ – α). Equate the expanded expression with 3 cos θ + 4 sin θ to find the value of θ. The correct answer is α = 53...° approximately.

AG
Answered by Anahita G. Maths tutor

21777 Views

See similar Maths A Level tutors

Related Maths A Level answers

All answers ▸

Find the equation of the straight line that passes through the points (1,2) and (2,4)


Find the coordinates of the point of intersection between the line L:(-i+j-5k)+v(i+j+2k) and the plane π: r.(i+2j+3k)=4.


If I had an equation with both 'x' and 'y' present, how would I find the gradient?


How do I find the inverse of a 2x2 matrix?


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