Here’s a sample SPM Question that requires you to use Double Angle and Half Angle Formulae.
Given that sin x = 5/13, and that x is obtuse. Calculate without using a calculator the value of
a) tan 2x
b) cos (x/2)
The technique used here is the same as for the Addition Formulae which I explained in this video.
b) Square root of (1/26)
Here’s the Video Tutorial if you’re stuck.
Part 1 (Question a)
Part 2 (Question b)
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