Ask Singapore Homework?
Upload a photo of a Singapore homework and someone will email you the solution for free.
Question
secondary 3 | A Maths
2 Answers Below
Anyone can contribute an answer, even non-tutors.
need help with part b only, i got the correct number but the signages wrong (the answer key is negative while i got positive)
Date Posted: 3 years ago
Views: 176
See 2 Answers
done
{{ upvoteCount }} Upvotes
clear
{{ downvoteCount * -1 }} Downvotes
Hope this helps eh, thanks.
Date Posted:
3 years ago
thx :)
sec(-2A)
= 1/cos(-2A)
= 1/cos(2A) (recall that cos(-θ) = cos(θ) )
= 1/(2cos²A - 1) (see formula sheet)
= 1/(2(-3/5)² - 1)
= 1/(2(9/25) - 1)
= 1/(18/25 - 1)
= 1/(-7/25)
= -25/7 or -3 4/7
= 1/cos(-2A)
= 1/cos(2A) (recall that cos(-θ) = cos(θ) )
= 1/(2cos²A - 1) (see formula sheet)
= 1/(2(-3/5)² - 1)
= 1/(2(9/25) - 1)
= 1/(18/25 - 1)
= 1/(-7/25)
= -25/7 or -3 4/7
thx :)
360 Tutoring Program