Answers created by Joe North

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• Is -0.45 a rational number?
  
• How can I prove the identity for cos(x+pi)=-cos x ?
  
• How do you find the derivative of #f(x)= 2/x#?
  
• What is the equation of the line tangent to # f(x)=(-x^2-1)/(x^2+4) # at # x=-3 #?
  
• What are the absolute extrema of #f(x)=9x^(1/3)-3x in[0,5]#?
  
• Is #f(x)=e^x/cosx-e^x/sinx# increasing or decreasing at #x=pi/6#?
  
• How do you use Integration by Substitution to find #intx^2*sqrt(x^3+1)dx#?
  
• If the arean of circle is 56 what is radius??
  
• If sin theta=2/3 with theta in quadrant 1, find sec theta?
  
• How do you differentiate #g(t)=1/(t^4+1)^3#?