Acepheid variable star is a star whose brightness alternately increases and decreases. suppose that cephei joe is a star for which the interval between times of maximum brightness is 6.5 days. its average brightness is 2.5 and the brightness changes by +/-0.45. using this data, we can construct a mathematical model for the brightness of cepheid joe at time t, where t is measured in days: b(t)=2.5+0.45sin(2πt/6.5) (a) find the rate of change of the brightness after t days. rate of change = equation editor equation editor (b) find the rate of increase after one day. rate of increase =

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step-by-step explanation:

a drawing really does here:

so i draw the horizontal line y=2 and the vertical line x=-2 at this intersection i put b (this is where my right angle is going to be).   so point b is at (-2,2).   point a is 5 units long and is also on y=2 so this point has to be (3,2) or (-7,2) -doesn't matter i will go with (3,2).

now we know c is at (-2,y) we don't know the y yet bet we know that c is on x=-2.

we have the area of the triangle is .5bh=12.5

we know the base length is 5 (ab)

we have the height is (2-y) if you look at your

plug in

.5(5)(2-y)=12.5

solve for y to get the y-coordinate for c

2.5(2-y)=12.5

divide both sides by 2.5 giving:

2-y=5

now subtract 2 on both sides

-y=3

y=-3

x-3y=4

step-by-step e

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