Figure 1 below shows the right-angled triangle $A B C$ , in which the angle at $C\,$ is a right angle and $A B = 5$ cm.

Figure for question 1

The angle $BAC\,$ is $θ\theta$ , where $\theta\,$ is measured in radians.

Given that $\theta\,$ is small, show that $AC≈5−5θ22\displaystyle AC \approx 5 - \frac{5\theta^2}{2}$ .

Hence find the length of $AC\,$ when $θ=0.1\theta = 0.1$ , giving your answer to four decimal places.

Figure 1 below shows the right-angled triangle $A B C$ , in which the angle at $C\,$ is a right angle and $A B = 5$ cm.

Figure for question 1

The angle $BAC\,$ is $θ\theta$ , where $\theta\,$ is measured in radians.

Given that $\theta\,$ is small, show that $AC≈5−5θ22\displaystyle AC \approx 5 - \frac{5\theta^2}{2}$ .

Hence find the length of $AC\,$ when $θ=0.1\theta = 0.1$ , giving your answer to four decimal places.

3.5 Trigonometry (A-level only)

3.5 Trigonometry (A-level only) Questions