Trig differentiation question (1 Viewer)

[enigma_1]

(a) Find the first and second derivatives of y = cosx + √3 sinx.
(b) Find the stationary points in the domain 0 ≤ x ≤ 2π and use the second derivative
to determine their nature.
(c) Find the points of inflexion.
(d) Hence sketch the curve for 0 ≤ x ≤ 2π.

From b onwards I'm screwing up

 

[braintic]

(a) Find the first and second derivatives of y = cosx + √3 sinx.
(b) Find the stationary points in the domain 0 ≤ x ≤ 2π and use the second derivative
to determine their nature.
(c) Find the points of inflexion.
(d) Hence sketch the curve for 0 ≤ x ≤ 2π.

From b onwards I'm screwing up

But you are only in year 11.

 

[rumbleroar]

For a, did you use the auxiliary method? It will make b,c,d much easier

 

[enigma_1]

Cheers mate, I'll do it now

 

[enigma_1]

Hey guys I can't do this, please help

 

[Carrotsticks]

Hey guys I can't do this, please help

cos(x)+root(3)sin(x) = 2cos(x - pi/3)

Try the usual differentiate, let the derivative equal zero etc stuff from here.