Answer:
See below.
Step-by-step explanation:
1. (1 / 2)[cos(a – b) – cos(a + b)]
= 1/2 ( cosa cosb + sina sinb - (cosa cosb - sina sinb)
= 1/2 ( cosa cosb - cosa cos b + sina sinb + sina sinb)
= 1/2 ( 2 sina sinb)
= sina sinb.
(I used the 2 identities cos(a - b) = cosa cosb + sina sinb) and
cos (a + b) = cosa cosb - sina sinb.)
2. sin (π/2 - x) = sin (π/2) cos x - cos(π/2) sin x
= 1 * cos x - 0 * sinx
= cosx - 0
= cos x.
(I used the identity sin(a - b) = sina cosb - cosa sinb
and the fact that sin(π/2) = 1 and cos (π/2) = 0. )
Answer With Step-by-step explanation:
C: 3
This is because 6 3/5 is a positive number, and 6 3/5 ÷ 2 1/5 = 3
Hope this was helpful! (brainliest please)
Answer:
Step-by-step explanation:
3*2x=6x, 3*5=10
So, 6x+10+4x = 5x+15
Add 6 and 4 which leaves you with 10x+10 = 5x+15
subtract 10 from 15 and that leaves you with 5 divided by 10x
x=2
Same for second equation
2*8x=16x and 2*3= 6
So 16x-6=16x+28
Add 6 to both sides so you get 34.
Now that 6 is gone you want x on one side so subtract 16x an it leaves you with 0. so X=34
The answer is a.
5x-7 = 4x+4 solve for x
substitute x in (x-7) to get 11-7
3y-4 = 11-7 solve for y
