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.

CH
Answered by Cameron H. Maths tutor

5612 Views

See similar Maths A Level tutors

Related Maths A Level answers

All answers ▸

Find dy/dx such that y=(e^x)(3x+1)^2.


Given that y = (( 4x + 1 )^3)sin(2x), find dy/dx.


What is the remainder when you divide 2x^3+7x^2-4x+7 by x^2+2x-1?


integrate (2x)/(x^2+1) dx with limits 1, 0


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:

© 2025 by IXL Learning