A curve has equations: x=2sin(t) and y=1-cos(2t). Find dy/dx at the point where t=pi/6

Since this question concerns parametric's, one may move to eliminate t from the equation to calculate dy/dx directly. However, in this case it is much easier to use the chain rule and realise that dy/dx=dy/dt*dt/dx=dy/dt/dx/dt. This is easier as both y and x are very simple to differentiate with respect to t and because the final part of the question involves substituting in a value of t. Differentiating y, the 1 disappears as it is a constant and the -cos(2t) goes to 2sin(2t) using the chain rule. X differentiates to 2cos(t). Using our chain rule from above, dy/dx=2sin(2t)/2cos(t). The 2s cancel. With our knowledge of the double angle formula sin(2t)=2sin(t)cos(t), leaving us with dy/dx=2sin(t)cos(t)/cos(t)=2sin(t). When t=pi/6 dy/dx=2sin(pi/6)=1.

Answered by Cameron H. Maths tutor

4984 Views

See similar Maths A Level tutors

Related Maths A Level answers

All answers ▸

Find all values of x in the interval 0 ≤ x ≤ 2pi for 2sin(x)tan(x)=3


Find the stationary pointsof the following: (y = x^3 - x^2 -16 x -17) and determine if each point is a maximum or minimum.


Given ∫4x^3+4e^2x+k intergrated between the bounds of 3 and 0 equals 2(46+e^6). Find k.


integrate 5x^2 + x + 2 and find the value of c if the curve lies on the coordinates (1,3)


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