Optional videos (K-A)

• Proof: Differentiability implies continuity-video (K-A)
• Justifying the power rule (K-A)
• Proof of power rule for positive integer powers (K-A)
• Proof of power rule for square root function (K-A)
• Limit of sin(x)/x as x approaches 0 (K-A)
• Limit of (1-cos(x))/x as x approaches 0 (K-A)
• Proof of the derivative of cos(x) (K-A)
• Product rule proof (K-A)