Boy Mow Chau's answer to Dave's Junior College 1 H2 Maths Singapore question.

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Boy Mow Chau
Boy Mow Chau's answer
317 answers (Tutor Details)
1st
x is small, but (π/4+x) is not small !
have to use compound angle formula to expand
sin(pi/4 + x) first ...

similarly, x is small, but 2x may not be small ...
use double angle formula for tan2x.

thereafter, expand & simplify, ignoring any powers of x3 & higher.
Dave
Dave
2 years ago
Thank you