Answer:
see explanation
Step-by-step explanation:
Using the sum to product identity
cosx + cosy = 2cos(
)cos( 
)
Consider left side
(cos5A +cos3A) + (cos15A + cos7A)
= 2cos(
)cos(
) + 2cos( 
) cos( 
)
= 2cos(
) cos(
) + 2cos(
)cos( )
= 2cos4AcosA + 2cos11A cos4A ← factor out 2cos4A from both terms
= 2cos4A( cos11A + cosA) ← repeat the process
= 2cos4A( 2cos(
)cos(
)
= 2cos4A(2cos(
)cos(
)
= 2cos4A(2cos6A cos5A)
= 4cos4Acos5Acos6A
= right side , thus verified
Answer: x < -3
Step-by-step explanation:
4x + 6 < -6
(Subtract 6 from both sides to isolate the x value)
4x < -12
(Divide by 4 to once again isolate the x value)
X < -3
Answer:
It says that for me too, there must be a problem with their system.
Try asking the specific problem you are having, so if someone had that specific problem before, they can walk you through it! :)
