title: I am writing a code based on some formulas;but my if statement does not seem to work(line 33)
body: <pre><code>W = int(input('Enter weight:'))
  
  b = [1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0]
  AR = [1, 2, 3, 4, 5]
  T = [50.99238, 50.05062, 49.07943, 48.05919, 47.00952, 45.92061, 44.79246, 43.62507,       42.42825, 41.18238, 39.90708, 38.60235, 37.24857, 35.86536, 34.4331, 32.97141, 31.48029, 29.94012, 28.37052, 26.76168, 25.1136]
  CL = [1.0]
  CD = [0.5]
  clmax = 2
  n = 0
  z = 0
  while b[n] &lt; 2.1 :
  
      while AR[z]&lt; 5.1:
          cl = CL[n]
          cd = CD[z]
          s = ((b[n]*b[n])/AR[z])                                
          V = ((2*W*9.81)/(1.2*s*clmax) ** 0.5)*1.1
          vlof = V/1.41
          Vlof = round(vlof)
          D = 0.5*cd*1.2*Vlof*Vlof*s
          L = 0.5*cl*1.2*Vlof*Vlof*s
          a = (9.81/W)*(T[Vlof]-D-O.O5(W-L))
          Sg = (V*V)/(2*a)
          if Sg &lt;= 30:
              print('IT WILL TAKEOFF')
          else:
              print('It will NOT takeoff')
          t/c = int(input('t/c ratio is:'))
          l = int(input('Taper ratio is:'))
          f = 0.005(1+1.5*((l-0.6)**2))
          e = (1/((1+0.12*V*V*0.003*0.003)(1+(0.142+(f*AR[z]*(10*t/c)**0.33)
              +(0.1/(4+AR[z])**0.8))
          if z &lt;= 5:                              # line 33 #
                                       z +=1
          else :
                                       break
  
     n+=1                
  </code></pre>
  
  <p>OUTPUT:</p>
  
  <pre><code>  File "&lt;ipython-input-49-d7d52927efb2&gt;", line 33
      if z &lt;= 5:
           ^
  SyntaxError: invalid syntax
  </code></pre>
  
  <p>This is a code which should tell me whether my aircraft will takeoff or not (on the input of a weight)
  I cannot seem to understand the reason why is this syntax invalid ?   </p>