1. The problem statement, all variables and given/known data Solve the stationary points of y=-sinx+cosx for domain -pi<x<pi 2. Relevant equations 3. The attempt at a solution Differentiate: d/dx=cosx+sinx But how do i solve?
ive got the answers as.. (-pi/4,-rt2) and (3pi/4, rt2) Are the answers wrong? I dont know how they got these?? because surly the x co-ordinate is 0???
If y = -sinx + cosx, what is dy/dx? Note that it is incorrect to say "d/dx = ..." If you meant dy/dx = ..., you have made a mistake. Try again. Also, your notation is not correct. d/dx is an operator that is written to the left of some function. In contrast, dy/dx is the derivative of y with respect to x.
so therefore: dy/dx=cosx+sinx. stationary points when diff = 0 so cosx+sinx=0 where do i go from here??
x-values lie on the x-axis, but stationary points lie on the curve, which might not even touch the x-axis. For example, the only stationary point on the graph of y = x^2 + 1 is at (0, 1). This is not a point on the x-axis.
No, dy/dx = -cosx - sinx To find the stationary points, set dy/dx to zero. -cosx - sinx = 0 ==> cosx + sinx = 0 ==> 1 + tanx = 0 (dividing both sides by cosx) Can you continue?