Upload Quadratic Calculator

Simple python program to calculate the quadratic formula of a sequence of numbers inputted

Author: GGearing314

QuadraticCalc.py

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+#GGearing
+#02/10/2017
+#Simple script to calculate the quadratic formula of a sequence of numbers and
+#recognises when the sequence isn't quadratic
+
+def findLinear(numbers):    ##find a & b of linear sequence
+    output=[]
+    a=numbers[1]-numbers[0]
+    a1=numbers[2]-numbers[1]
+    if a1==a:
+        b=numbers[0]-a
+        return (a,b)
+    else:
+        print("Sequence is not linear")
+        
+sequence=[]
+first_difference=[]
+second_difference=[]
+for i in range(4):  #input
+    term=str(i+1)
+    inp=int(input("Enter term "+term+": "))
+    sequence.append(inp)
+    
+for i in range(3):
+    gradient=sequence[i+1]-sequence[i]
+    first_difference.append(gradient)
+for i in range(2):
+    gradient=first_difference[i+1]-first_difference[i]
+    second_difference.append(gradient)
+    
+if second_difference[0]==second_difference[1]:  #checks to see if consistent
+    a=second_difference[0]/2
+    subs_diff=[]
+    for i in range(4):
+        n=i+1
+        num=a*(n*n)
+        subs_diff.append((sequence[i])-num)
+    b,c=findLinear(subs_diff)
+    print("Nth term: "+str(a)+"n^2 + "+str(b)+"n + "+str(c)) #outputs nth term
+else:
+    print("Sequence is not quadratic")
+