1. Which is a solution to the equation below? sin2xsecx=1
2. What is the exact value of cos15 degrees?
3. Which expression is equivalent to the expression below? cos^2 xsin^2?
4. What is the exact value of cos2theta? one side is 8 and the other is 15
5. The angle x lies in quadrant ll. If sinx=3/5, then what is the exact value of tan2x?
3 answers
PLEASE HELP ME OUTTTTTTTTTTTTTTTTTTT
This assignment is obviously meant to study the double angle formulas
1.
sin 2x secx = 1
2sinxcosx(1/cosx) = 1
sinx = 1/2
so x is in I or II
x = 30 or 150 degrees or pi/6, 5pi/6 radians
2. use cos2A = 1 - 2cos^2 A
cos 30 = 1 - 2cos^2 A
you should know cos 30, sub it in and simplify
how about you trying some of these.
1.
sin 2x secx = 1
2sinxcosx(1/cosx) = 1
sinx = 1/2
so x is in I or II
x = 30 or 150 degrees or pi/6, 5pi/6 radians
2. use cos2A = 1 - 2cos^2 A
cos 30 = 1 - 2cos^2 A
you should know cos 30, sub it in and simplify
how about you trying some of these.
in #2 I had my formula backwards
should say
cos 2A = 2cos^2 A - 1
cos 30 = 2cos^2 15 - 1
should say
cos 2A = 2cos^2 A - 1
cos 30 = 2cos^2 15 - 1