What is the value of the x-coordinate of point A? (a) sin(pi/5)
(b) cos (pi/5)
(c) sin (6pi/5)
(d) cos (6pi/5)
(e) sin (9pi/5)

D.) cos(6π/5)

Step-by-step explanation:

In a unit circle, cosine is defined as x-coordinate and sine is defined as y-coordinate.

This is because cosine is defined as x/r but since it’s a unit circle, r = 1 therefore, cosine = x,

Sine is defined as y/r but it’s a unit circle so sine = y.

Therefore, we ignore choices with sine.

Next, since this π/5 angle is in the third quadrant. π/5 is supposed to be in the first quadrant so to convert from first quadrant angle or reference angle to the third quadrant angle or opposite side, add the reference angle or π/5 by π.

Therefore, π/5 + π = π/5 + 5π/5

= 6π/5

Since we want to find x-coordinate which is cosine, therefore.

The answer is cos(6π/5)

a 360 degree rotation

step-by-step explanation:

hello from mrbilldoesmath!

answer:   (7x + 6y) ( 49x^2 - 42xy + 36y^2)

discussion:

in general, the factorization of a^3 + b^3 is

a^3 + b^ 3 = (a + b) ( a^2 - ab + b^2)

in our case note that 343 = 7^3 and 216 = 6^3 so the equation becomes:

343x^3 + 216y^3 = (7x)^3 + (6y)^3

if you think of a (above) as 7x and b as 6y the factorization becomes

343x^3 + 216y^3 =

((7x + 6y) (   (7x)^2 - 7x*6y + (6y)^2)   =

(7x + 6y) ( 49x^2 - 42xy + 36y^2)

you,

mrb

(a + b) (a^2 - a b + b^2)