# [PYTHON] Combine polynomial functions

``````from IPython.display import HTML

HTML('''
<script>
code_show=true;
function code_toggle() {
if (code_show){
\$(\'div.input\').hide();
} else {
\$(\'div.input\').show();
}
code_show = !code_show
}
</script>
<form action="javascript:code_toggle()">
<input type="submit" value="Toggle code">
</form>
''')
``````
``````import numpy as np
import pandas as pd
import matplotlib.pyplot as plt
import seaborn as sns
%matplotlib inline
plt.rcParams['font.size']=15

def plt_legend_out(frameon=True):
plt.legend(bbox_to_anchor=(1.05, 1), loc='upper left', borderaxespad=0, frameon=frameon)
``````

# Linear expression

``````def f(x):
return x

x = np.linspace(-10,10,100)

plt.plot(x,f(x))
plt.axvline(x=0,color='gray',lw=0.5)
plt.axhline(y=0,color='gray',lw=0.5)
plt.show()
``````

``````def f(x):
return -x**2

x = np.linspace(-10,10,100)

plt.plot(x,f(x))
plt.axvline(x=0,color='gray',lw=0.5)
plt.axhline(y=0,color='gray',lw=0.5)
plt.show()
``````

``````def f(x):
return x**4

x = np.linspace(-10,10,100)

plt.plot(x,f(x))
plt.axvline(x=0,color='gray',lw=0.5)
plt.axhline(y=0,color='gray',lw=0.5)
plt.show()
``````

# combination

``````def f(x):
return 0.9*x**4 - (50*x**2) + 50*x + 200

x = np.linspace(-10,10,100)

plt.plot(x,f(x))
plt.axvline(x=0,color='gray',lw=0.5)
plt.axhline(y=0,color='gray',lw=0.5)
plt.show()
``````

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