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Mathematics

2 answers:

ollegr [7]3 years ago

8 0

Answer:

SA = 16x^2 +30x+6

Step-by-step explanation:

The surface area is given by

SA = 2 (lw + lh + wh)

The length is 2x, the width is (x+3) and the height is (2x+1)

SA = 2 ((2x)*(x+3) + (2x)*(2x+1) + (x+3) (2x+1))

We need to distribute

SA = 2 ((2x^2+6x) + (4x^2+2x) + (2x^2 +6x+x+3))

Combine like terms

SA = 2 (2x^2+ 4x^2+2x^2+6x+2x +6x+x+3)

SA = 2 (8x^2+15x+3)

Multiply by 2

SA = 16x^2 +30x+6

lana66690 [7]3 years ago

4 0

Answer:

Step-by-step explanation:

Surface area = sum of all six faces

=2(2x)(x+3) + 2(2x)(2x+1) + 2(x+3)(2x+1)

=4x^2+12x + 8x^2+4x + 4x^2+14x+6

=16x^2 + 30x + 6

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Nikitich [7]

Answer:

$15\sqrt{3}$

7 0

3 years ago

I NEED HELP PLEASEE

xenn [34]

$\bf \cfrac{1+cot^2(\theta )}{1+csc(\theta )}=\cfrac{1}{sin(\theta )} \\\\[-0.35em] ~\dotfill\\\\ \cfrac{1+cot^2(\theta )}{1+csc(\theta )}\implies \cfrac{1+\frac{cos^2(\theta )}{sin^2(\theta )}}{1+\frac{1}{sin(\theta )}}\implies \cfrac{~~\frac{sin^2(\theta )+cos^2(\theta )}{sin^2(\theta )}~~}{\frac{sin(\theta )+1}{sin(\theta )}}\implies \cfrac{~~\frac{1}{sin^2(\theta )}~~}{\frac{sin(\theta )+1}{sin(\theta )}}$

$\bf \cfrac{1}{\underset{sin(\theta )}{~~\begin{matrix} sin^2(\theta ) \\[-0.7em]\cline{1-1}\\[-5pt]\end{matrix}~~ }}\cdot \cfrac{~~\begin{matrix} sin(\theta ) \\[-0.7em]\cline{1-1}\\[-5pt]\end{matrix}~~}{sin(\theta )+1}\implies \cfrac{1}{sin^2(\theta )+sin(\theta )} \\\\[-0.35em] ~\dotfill\\\\ ~\hfill \cfrac{1+cot^2(\theta )}{1+csc(\theta )}\ne \cfrac{1}{sin(\theta )}~\hfill$