# Tutor profile: Ohmeko O.

## Questions

### Subject: HTML Programming

What are the three ways you can apply CSS to your HTML website?

You can use CSS to dress up your HTML structure in three ways: inline, internal style sheet, or external style sheet. Way #1: Inline CSS In order to use inline css you have to place the css inside the beginning tag and use the style attribute like so: <h1 style ="color:purple;"> Hi! </h1> Way #2: Internal CSS In order to use Internal CSS you have to place your css code inside a <style> </style> tag inside your <head></head> tag on an html document. You then put the tag you want to modify, class to modify or id to modify in the following fashion: <head> <style> h1 { color: purple; } <\style> <\head> Way #3 External CSS In order to use external css you must place all your css code in a separate .css file and use the <link> </link> tag to connect .html to a .css file. You would do it this way: Let's say you have awesome.html you want to use CSS to modify how this .html looks. You would place this code in your awesome.html <head> <link rel="stylesheet" type="text/css" href="supercool.css"> </head> Then in that same directory you would make a plaintext file named "supercool.css" and place your CSS in that file.

### Subject: Electrical Engineering

A 75 $$\Omega$$ coaxial transmission line has a length 2.0 cm and is terminated with a load impedance of $$37.5 + j75 \Omega$$. If the dielectric constant of the line is $$\epsilon_r = 2.56$$ and the frequency is 3.0 GHz, find the input impedance to the line, the reflection coefficient at the load, the reflection coefficient at the input, and the SWR on the line.

Step 1) Write down what we are given: $$Z_o = 75 \Omega $$ coaxial line, Length of Line is 2.0 cm, $$ Z_L = 37.5+j75 \Omega $$, $$\epsilon_r = 2.56$$, $$ f_c = 3.0 $$ GHz. Step 2) Find the reflection coefficient at the load. The reflection coefficient $$\Gamma_L$$ is defined as: $$Gamma_L = \frac{Z_L - Z_o}{Z_L + Z_o} = \frac{37.5+j75 -75}{37.5+j75 +75} = 0.078+j0.615$$ Step 3) Find the SWR of the line. The SWR is defined by the following equation: $$SWR = \frac{V_{max}}{V_{min}} = \frac{Vp(1+|\Gamma_L|)}{Vp(1+|\Gamma_L|)} = \frac{1+0.6202}{1-0.6202} = 4.266$$ Step 4) Find the reflection coefficient at the input. The reflection at the input can be obtained by multiplying the reflection at the load by the delay introduced to the reflection by the length of the line: $$\Gamma_{in} = \Gamma(d) = \Gamma_L e^{-2j\beta d} = 0.602\angle(1.446-2*\frac{2\pi}{\lambda}*2*10^{-2}) $$ We have to convert 82.875 into radians for the calculation which equates to: $$82.875^{\circ} * \frac{\pi}{180^{\circ}} = 1.446$$ Thus we get the reflection at the input to be: $$\Gamma_{in} = 0.6202\angle 212.08 $$ Step 5) Find the input impedance of the line. The input impedance of the line could be found with this formula: $$Z_{in}(d) = \frac{Z_{L} + Z_{o}\tan(\beta*l)}{Z_{o} + Z_{L}\tan(\beta*l)} = 18.95 - j20.30$$

### Subject: Algebra

Find the solutions to $$|3x + 9| > -2$$

The solutions to the above inequality is: Step 1) You have to realize that you have an absolute value so you have two cases. Step 2) You have two equations to solve: $$3x+9 > -2$$ and $$-3x-9 > -2$$ Step 3) First equation solution to solve is $$3x + 9 > -2$$ $$3x > -11 $$ $$x > \frac{-11}{3}$$ Step 4) Second equation solution to solve is $$-3x-9 > -2$$ $$-3x > 7$$ $$ x > \frac{-7}{3}$$ Step 5) The solution to the inequality is thus $$ x > \frac{-7}{3}$$ and $$x > \frac{-11}{3}$$

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