Skip to content
MathsGenie logo
Quick links
Open app

Course home

  1. A Level
  2. Maths OCR (MEI)
  3. Question bank

1.7.21 Use identities to solve equations (A-level only)

EasyMediumHard
12345678910111213141516171819202122232425
Question 8

In robotic kinematics, the equilibrium tilt angle α\alphaα of a stabilizer, measured in radians, is modeled by a balance of forces. This equilibrium occurs when the following equation is satisfied:

12sin⁡αcos⁡α2sin⁡α+5=2tan⁡α,sin⁡α≠−2.5 \frac{12\sin\alpha \cos\alpha}{2\sin\alpha + 5} = 2\tan\alpha, \quad \sin\alpha \neq -2.5 2sinα+512sinαcosα​=2tanα,sinα=−2.5
a.

Demonstrate that this equilibrium equation can be expressed in the form

6sin⁡3α+2sin⁡2α−sin⁡α=0 6\sin^3\alpha + 2\sin^2\alpha - \sin\alpha = 0 6sin3α+2sin2α−sinα=0
[4]
b.

Determine the specific tilt angles α\alphaα in the interval −π2<α<π2-\frac{\pi}{2} < \alpha < \frac{\pi}{2}−2π​<α<2π​ that satisfy this condition, giving your answers to 3 decimal places.

[3]

1.7.21 Use identities to solve equations (A-level only) Questions

  1. A Level
  2. /Maths
  3. /1.7.21 Use identities to solve equations (A-level only)