A very good morning to you Sonia!!! Here are my workings for this question.

We will need to leave part (i) answer in exact form or at least show it as part of the working (before writing out the decimals) because we will need this exact form for part (ii), since the value to be obtained contains an exact form.

For part (ii), we cut the diagram into several pieces and compute it. Without this "hence" stipulation, we can attempt to integrate the graph with respect to y. However, we soon find that x = inverse sin y and we are unable to integrate this function in the O Level (it can be done in the A Levels though). Therefore, we have no choice but to cut the diagram into several parts to obtain the shaded area.

I hope my workings help you! Let me know if my workings are unclear and I will do my best to explain them in more detail!

Hi Sonia! Here is a list of the relevant special angles for acute angles which you will need to know for A Maths.

Recognise that the degree form skips 15 and 75. To find the sine, cosine or tangent of these two angles, we will need to use the addition or subtraction angle formula found in your formula list.

Also recognise that the numerators of the radian form are all in pi while the denominators of the radian form are all factors of 12, other than 12 and 1, in decreasing order.

I have tabulated two forms for you. You can follow either form depending on the form which you have learnt and the form which you prefer.