Answer:
The answer w'll be obtained using formulas
cos(a+b) = cosacosb - sinasinb
cos(a-b) = cosacosb + sinasinb
Step-by-step explanation:
Using the trigonometric formula of addition and subtraction of cosine
cos(a+b) = cosacosb - sinasinb
cos(a-b) = cosacosb + sinasinb
w'll get the desired answer.
To be solve
L.H.S = R.H.S
sinasinb = (cos(a-b)-cos(a+b)/2
as we know that <u><em>cos(a+b) = cosacosb - sinasinb</em></u>
sinasinb = (cos(a-b) - (cosacosb -sinasinb))/2
as we know that <u><em>cos(a-b) = cosacosb + sinasinb</em></u>
sinasinb = ((cosacosb + sinasinb) - (cosacosb -sinasinb))/2
sinasinb = (cosacosb + sinasinb - cosacosb + sinasinb)/2
sinasinb = (2sinasinb)/2
sinasinb = sinasinb
hence L.H.S = R.H.S
Let's look at the second equation and try multiplying it by 4:
4 * (3x + ky) = 4 * 27
Which gives us:
12x + 4ky = 108
This looks almost exactly like the first equation except that instead of -20y, there is 4ky. We could try making them equal to each other and solving for k:
-20y = 4ky
-20 = 4k
k = -5
Then, the answer is k = -5.
X=12y there is no conventional way of solving precisely.
First find the equation of y.
Find the slope m.
.
Pick one point, I'll pick (-3, 9). Insert coordinates in equation then compute n.
.
The equation of a line y is:
.
The perpendicular line 
is same like the normal line except its slope m becomes:
.
The equation of a perpendicular bisector is thus:
.
Hope this helps.
Answer:
y = 
x
Step-by-step explanation:
Given that y varies directly as x then the equation relating them is
y = kx ← k is the constant of variation
To find k use either of the 2 given points
Using (- 9, - 3), then
k = 
= 
=
y = x ← equation of function
