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Exam 1. Math 1231: Single-Variable Calculus. Question 1: Limits. Question 2: Implicit Function. 1. Prove there is a root for the equation cosθ = θ in the interval (0, π).
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Exam 1 Math 1231: Single-Variable Calculus
Question 2: Implicit Function • 1. Prove there is a root for the equation cosθ=θ in the interval (0, π). • Define f(θ)=cosθ-θ, f(0)=1, f(π)=-1-π, f(θ) have opposite sign on the boundary points, IVP implies there is a root. • 2. Prove there is a root for the equation cosy=y in the interval (0, π). • Define f(y)=cosy-y, f(0)=1, f(π)=-1-π, f(y) have opposite sign on the boundary points, IVP implies there is a root. • 3. Prove there is a root for the equation cosx=x in the interval (0, π). • Define f(x)=cosx-x, f(0)=1, f(π)=-1-π, f(x) have opposite sign on the boundary points, IVP implies there is a root. • Prove there is a root for the equation sqrt(y)=-1+y in the interval (0, 4). • Define f(y)=sqrt(y)+1-y, f(0)=1, f(4)=-1, f(y) have opposite sign on the boundary points, IVP implies there is a root.
Question 2: Implicit Function Use parenthesis!!!
Question 3: Continuity and Derivative • f(x) is continuous only if limx0 f(x)=f(0)=0. • How to show that limx0 x2sin(1/x) =0?
Question 3: Continuity and Derivative Squeeze theorem
Question 3: Continuity and Derivative • f(x) is continuous only if limx0 f(x)=f(0)=0. • How to show that limx0 x2sin(1/x) =0? -1 <= sin(1/x) <= 1 -x2 <= x2sin(1/x) <= x2. Note that -x2 and x2 approach 0 as x goes to 0, so does x2sin(1/x).