Hi there!
We are given:
cos(7x)cos(4x) = -1 - sin(7x)sin(4x)
Begin by moving all terms with variables to one side:
cos(7x)cos(4x) + sin(7x)sin(4x) = -1
The corresponding trig identity is cos(A - B). Thus:
cos(7x - 4x) = cos(7x)cos(4x) + sin(7x)sin(4x) = -1
cos(3x) = -1
cos = -1 at π, so:
3x = π
x = π/3
We can also find another solution. Let 3π = -1:
3x = 3π
x = π
Thus, solutions on [0, 2π) are π/3 and π.
Answer:
64.2580645161 words in a minute
Step-by-step explanation:
Hope that helps!
Answer:
$54.26
Step-by-step explanation:
Convert the percentage into a decimal by moving the decimal point 2 places to the left or divide by 100.
This will give you .0825.
Multiply this number by $50 and add it to it