We can re-create the quadratic equation by
(x -3) * (x -2)
x^2 -5x + 6 = 0
Answer:
the common ratio is either 2 or -2.
the sum of the first 7 terms is then either 765 or 255
Step-by-step explanation:
a geometric sequence or series of progression (these are the most common names for the same thing) means that every new term of the sequence is created by multiplying the previous term by a constant factor which is called the common ratio.
so,
a1
a2 = a1×f
a3 = a2×f = a1×f²
a4 = a3×f = a1×f³
the problem description here tells us
a3 = 4×a1
and from above we know a3 = a1×f².
so, f² = 4
and therefore the common ratio = f = 2 or -2 (we need to keep that in mind).
again, the problem description tells us
a2 + a4 = 30
a1×f + a1×f³ = 30
for f = 2
a1×2 + a1×2³ = 30
2a1 + 8a1 = 30
10a1 = 30
a1 = 3
for f = -2
a1×-2 + a1×(-2)³ = 30
-10a1 = 30
a1 = -3
the sum of the first n terms of a geometric sequence is
sn = a1×(1 - f^(n+1))/(1-f) for f <>1
so, for f = 2
s7 = 3×(1 - 2⁸)/(1-2) = 3×-255/-1 = 3×255 = 765
for f = -2
s7 = -3×(1 - (-2)⁸)/(1 - -2) = -3×(1-256)/3 = -3×-255/3 =
= -1×-255 = 255
At the respective max and min values
Answer:
50 degrees
Step-by-step explanation:
Okay! So first off, because this is NOT a right triangle, we can't use soh cah toa. That means we can either use the law of sines or the law of cosines.
Because we only have sides here and no angles, we are forced to use the law of cosines.
c^2 = a^2 + b^2 − 2ab cos(C)
c = 6
b = 7.5
a = 6.5
36 = 6.5^2 + 7.5^2 - 2(6.5)(7.5)cos(C)
36 = 98.5 - 97.5cos(C)
-62.5 = -97.5cos(C)
0.641 = cos(C)
angle C = cos^-1(0.641)
angle C = 50.13 which is around 50 degrees
Remember! A dumb thing i always used to do in geometry was use radians instead of degrees, be sure to use degrees here because you are looking for degrees. Radians are for things involving not degrees, but PI.
