12. ∆ABD is similar to ∆PQD, so
QD/z = BD/x
Likewise ∆CDB is similar to ∆PQB, so
QB/z = BD/y
Since QD + QB = BD, you have
QD/z + QB/z = BD/x + BD/y
BD/z = BD/x + BD/y
Dividing by BD gives the desired result:
1/x + 1/y = 1/z
13. Triangles ABD, BCD, and ACB are all similar. This means
AB/AC = AD/AB
AB² = AC×AD = (4 cm)×(9 cm)
AB² = 36 cm²
AB = 6 cm
and
BD/CD = AD/BD
BD² = CD×AD = (5 cm)×(4 cm)
BD² = 20 cm²
BD = 2√5 cm
Answer:
1/9 is a rational number because rational numbers are numbers that you can write as a fraction.
Hi there!
We are given the function -

and are told to find the limit of the function.
The limit would be n approaches infinity, giving us an answer of
-1.
Here is how you solve this:

Divide by (n + 1)! -

Now, we can refine the function -

Now, just simplify. This gives us -

We can use the rule

to simplify the whole thing to get 1. Finally, we plug it back into our second derived equation to get 1/-1, which simplifies to -1. Therefore, the answer is
-1. Hope this helped and have a great day!
8 times 9 divided by 2 the answer is 36