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.
The 2nd option is correct
Answer:
4th and 5th option
Step-by-step explanation:
you can easily add eqn 1 and 2 to get rid of the y term for 4th option and get rid of x term by addition as well for the 5th option
this is a topic on simultaneous equation. If you wish to explore more into this topic you can give me a follow on Instagram (learntionary) I'll be posting the notes for this topic and some other tips :)
The answer is -6.825 in fraction form, it would be -6 33/40
Answer:
oye me puedes ayudar a mi tarea
es del cuento el príncipe feliz
