When asked to prove for identities, try to start from either Left or Right Hand Side of the equation (LHS/RHS) and then expand/factorise terms and use trig identities to turn them into what is required (if using from LHS prove that it becomes RHS and vice versa). These questions really test you on basics such as algebraic manipulations like (a+b)(a-b),(a+b)^2 even grouping of fractions with common denominator as seen in question 9. The trig identities side also very simple with things like knowing what sec/cosec/cot is, (A): (sin(x))^2+ (cos(x))^2= 1, (B): (tan(x))^2 = (sec(x))^2 - 1.

The questions doesn’t require things like double angle formula/compound formula/addition or subtraction formula of which can be found in the formula sheet.

One of the difficulty I had when first doing trig is getting comfortable with squaring the trig functions and understanding what they look like when multiplied together. sinx/cosx/tanx are independent terms think of them as one big X. So when X • X = X^2 etc. 2•X=2X etc same goes for addition and subtraction.

Notice how (B) is derived by dividing all terms in (A) with (cos(x))^2.