Chapter 6: Trigonometric functions Notes

Transformations of trigonometric graphs and modelling, differentiating and integrating sine, cosine and tangent, tangents, curve sketching, optimisation, areas, and the proof that the derivative of sin x is cos x.

Sections

  1. 6A Trigonometric graphs and modelling Mastered

    Amplitude, period, phase shift and mean value of y = a sin n(x − h) + k, sketching transformed trigonometric graphs, and using trigonometric functions to model periodic situations such as tides.

  2. 6B Differentiating trigonometric functions Mastered

    The derivatives of sin x, cos x and tan x in radians, the chain rule standard forms, and differentiating products, quotients, powers and compositions involving trigonometric functions.

  3. 6C Applications of trigonometric derivatives Mastered

    Tangents and normals to trigonometric curves, finding stationary points and sketching curves such as y = sin x + cos x and y = x + sin x, and optimisation problems involving angles.

  4. 6D Integrating trigonometric functions Mastered

    Standard integrals of sin, cos and sec squared, definite integrals, finding a primitive from an initial condition, the integral of tan x, and the reverse chain rule with trigonometric functions.

  5. 6E Areas with trigonometric functions Mastered

    Finding areas between trigonometric curves and the x-axis, splitting at the x-intercepts, and finding areas between two trigonometric curves.

  6. 6F Proving the derivative of sin x Mastered

    The limit of sin h over h as h tends to zero, proved geometrically, and the proof from first principles that the derivative of sin x is cos x, with the derivatives of cos x and tan x that follow.

Formula sheet