Use de moivre's theorem to write the complex number in trigonometric form: (cos(3pi/5) + i sin (3pi/5))^3

By De Moivre's theorem,

We can stop here ...

# # #

... but we can also express these trig ratios in terms of square roots. Let and let . Then recall that

On the left, so that

Since , we're left with

because we know to expect . Then from the Pythagorean identity, and knowing to expect , we get

Both and are -periodic, so that

and

so that the answer we left in trigonometric form above is equal to

c.   x=2.4cm

step-by-step explanation:

similar triangles are triangles which have the same shape but not the same size. this means their angle measures are equal but their side lengths are not instead they are proportional. to solve, we will set up a proportion and solve.

a proportion is two equal ratios set equal to each other. we form the ratios by finding corresponding sides (sides which match to each other on both triangles by their position). out ratios will be one side of the small triangle over the corresponding side on the big triangle as shown below:

.

to solve the proportion, we'll cross multiply by multiplying numerator with denominator across the equal sign.

you should talk someone who owns the website about it. you did not deserve to have all that hard work and time taken away. id watch videos of little puppies to cool you down, and maybe some nacho cheese doritos.