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 #1
avatar+9468 
+5

 

By the SAS congruence theorem,  △PQT ≅ △SRT  So...

 

m∠QPT  =  m∠RST  =  37°

 

m∠QTP  =  180° - 50°   =   130°

 

m∠PQT  =  180° - 37° - 130°  =  13°

 

Since  QT = RT  we can substitute  QT  in for  RT in the next equation.


\(RT+TP\ =\ 11\\~\\ QT+TP\ =\ 11\\~\\ QT\ =\ 11 - TP\)

 

Now we can substitute  11 - TP  in for  QT in the next equation.

 

By the Law of Sines,

 

\( \frac{TP}{\sin13^\circ} \ =\ \frac{QT}{\sin37^\circ}\\~\\ TP\cdot\frac{\sin37^\circ}{\sin13^\circ}\ =\ QT\\~\\ TP\cdot\frac{\sin37^\circ}{\sin13^\circ}\ =\ 11-TP\\~\\ TP\cdot\frac{\sin37^\circ}{\sin13^\circ}+TP\ =\ 11\\~\\ TP\cdot(\frac{\sin37^\circ}{\sin13^\circ}+1)\ =\ 11\\~\\ TP\ =\ 11\div(\frac{\sin37^\circ}{\sin13^\circ}+1)\\~\\ TP\ =\ \frac{11\sin13^\circ}{\sin37^\circ+\sin13^\circ} \)

 

Now that we know the length of  TP ,  we can find the length of  QT.

 

\(QT\ =\ 11-TP\\~\\ QT\ =\ 11-\frac{11\sin13^\circ}{\sin37^\circ+\sin13^\circ}\)

 

Finally, we can use the Law of Sines again to find  QP.

 

\(\frac{QP}{\sin130^\circ}\ =\ \frac{TP}{\sin13^\circ}\\~\\ QP\ =\ TP\cdot\frac{\sin130^\circ}{\sin13^\circ}\\~\\ QP\ =\ \frac{11\sin13^\circ}{\sin37^\circ+\sin13^\circ}\cdot\frac{\sin130^\circ}{\sin13^\circ}\\~\\ QP\ =\ \frac{11\sin130^\circ}{\sin37^\circ+\sin13^\circ}\)

 

So we have found:

 

\(\begin{array}{c} TP&=& \frac{11\sin13^\circ}{\sin37^\circ+\sin13^\circ}& \approx& 2.993\\~\\ QT& =& 11-\frac{11\sin13^\circ}{\sin37^\circ+\sin13^\circ}& \approx& 8.007\\~\\ QP& =&\frac{11\sin130^\circ}{\sin37^\circ+\sin13^\circ}& \approx& 10.192 \end{array}\)

 

And all lengths are in meters.

Jul 20, 2019
 #1
avatar+9468 
+5

a + ab2   =   40b

a - ab2   =   -32b

 

The purple values are equal to each other and the blue values are equal to each other.

 

a - ab2   =   -32b                     Add  40b  to both sides of the equation.

 

a - ab2 + 40b   =   -32b + 40b        Since  a + ab2  =  40b   we can substitute  a + ab2  in for  40b

 

a - ab2 + a + ab2   =   -32b + 40b      The elimination method is really just like substitution  smiley

 

a - ab2 + a + ab2   =   -32b + 40b      Simplify both sides by combining like terms.

 

2a   =   8b          Divide both sides of the equation by  8

 

\(\frac14\)a  =  b

 

Now we can substitute this value for  b  into one of the original equations.

 

a + ab2  =  40b

                                    Substitute   \(\frac14\)a   in for   b

a + a(\(\frac14\)a)2  =  40(\(\frac14\)a)

                                    Simplify both sides of the equation.

a + \(\frac{1}{16}\)a3   =   10a

                                    Multiply through by  16

16a + a3  =  160a

                                    Subtract  16a  from both sides and subtract  a3  from both sides

0  =  144a - a3

                                    Factor  a  out of both terms on the right side

0  =  a( 144 - a2 )

                                           Factor   144 - a2   as a difference of squares

0  =  a( 12 - a )( 12 + a )

                                           Set each factor equal to  0  and solve for  a

0  =  a ___ or ___ 12 - a  =  0 ___ or ___ 12 + a  =  0

 

 

a  =  0   a  =  12   a  =  -12  
Jul 19, 2019
 #4
avatar+9468 
+5

Out of curiosity, I wanted to see a length comparison between your answer and my answer:

 

 

\(\cot(\arctan(\cos(\arctan(\cot(\arctan(\cot(\arctan(\cos(\arctan(\cot(\arctan(\cot(\arctan(\cos(\arctan(\cot(\arctan(\cos(\arctan(\cot(\arctan(\cos(\arctan(\cos(0)))))))))))))))))))))))))\)

 

25 total basic functions

 

Here is WolframAlpha's result: https://www.wolframalpha.com/input/?i=cot(arctan(. . .

 

 

versus

 

 

\(\cot(\arctan(\cos(\arctan(\cos(\arctan(\cos(\arcsin(\cos(\arctan(\cos(\arcsin(\cos(\arctan(\cos(\arctan(\cos(0)))))))))))))))))\)

 

17  total basic functions

 

Here is WolframAlpha's result: https://www.wolframalpha.com/input/?i=cot(arctan(. . .

.

smiley

 

.

Jul 17, 2019