Select the proper placement for parentheses to speed up the addition for the expression 4 + 6 + 5

Mathematics

2 answers:

nata0808 [166]3 years ago

6 0

Im guessing that by making 10 it will speed up the addition process so it should be
B since (6+4) = 10 then +5 =15

vlabodo [156]3 years ago

6 0

The answer is B becuase 6+4=10 10+5=15

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What is the value of i^20+1?

ICE Princess25 [194]

You know

$i^2=-1$

Squaring both sides gives

$(i^2)^2=(-1)^2\implies i^4=1$

Then raising both sides to any integer power $n$ gives

$(i^4)^n=1^n\implies i^{4n}=1$

That is, any power of $i$ where the power is a multiple of 4 will always be equal to 1.

$i^{20}+1=1+1=2$

But perhaps you mean to write 20+1 as the exponent, in which case

$i^{20+1}=i^{20}i=i$

8 0

3 years ago

In the figure below, BCA ~ STR. Find cos C, sin C, and tan C. Round your answers to the nearest hundredth.

arsen [322]

Answer:

$\sin C\approx0.85\\\\\cos C \approx0.52\\\\\tan C\approx1.63$

Step-by-step explanation:

According to the trigonometric ratios in aright triangle :

$\sin x =\dfrac{\text{Side opposite to x}}{\text{Hypotenuse}}\\\\\cos x =\dfrac{\text{Side adjacent to x}}{\text{Hypotenuse}}\\\\\tan x=\dfrac{\sin x}{\cos x}$

Given: ΔBCA ~ ΔSTR

Since , corresponding angles of two similar triangles are equal.

So, ∠C = ∠T ...(i) [Middle letter]

In triangle STR

$\sin T=\dfrac{\text{Side opposite to T}}{\text{Hypotenuse}}\\\\=\dfrac{26.4}{30.9}\approx0.85\\\\\cos x =\dfrac{\text{Side adjacent to T}}{\text{Hypotenuse}}\\\\=\dfrac{16.2}{30.9}\approx0.52\\\\\tan T=\dfrac{\sin T}{\cos T}\\\\=\dfrac{0.85}{0.52}\approx1.63$ ...(ii)