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    Berkeley preliminary exam Spring 1987

    SRC-BERKELEY-PRELIM-SPRING-1987

    Area
    Prelim
    Status
    draft
    Source

    20 problems.

    1. If every continuous real-valued function on \(K\subset\mathbb R^n\) is bounded, then \(K\) is compact
    2. Local and global injectivity of \((u,v)\mapsto(u+v,u^2+v^2)\) on \(u>v\)
    3. If \(f^2\) and \(f^3\) are analytic, then \(f\) is analytic
    4. Polynomial representation of every function on a finite field
    5. Periodization of a decaying continuous function and integration against periodic functions
    6. Derivative bound from \(|f(z)|\le C/(1-|z|)\) on the unit disk
    7. Self-adjoint form of a second-order linear ODE
    8. Derivatives preserve a strict half-plane containing all polynomial roots
    9. Rational linear systems solvable over \(\mathbb C\) are solvable over \(\mathbb Q\)
    10. Embedding of a finite group of order \(n\) in the real orthogonal group \(O(n)\)
    11. The equation \(ae^x=1+x+x^2/2\) has exactly one real root
    12. Approximation of \(\int_0^{1/2}\sin x/x\,dx\) within \(0.005\)
    13. Bounded first partial derivatives force a removable puncture for a \(C^1\) real function
    14. The unique noncyclic group of order four has automorphism group \(S_3\)
    15. Entire functions sending unbounded sequences to unbounded sequences need not be polynomials — Problem 15
    16. The pointwise supremum of a uniformly bounded equicontinuous family is continuous
    17. A finite-dimensional differentiation-invariant function space is the kernel of a constant-coefficient ODE
    18. Commuting diagonalizable matrices are simultaneously diagonalizable — Problem 18
    19. Every finite subgroup of the multiplicative group of a field is cyclic
    20. The integral \(\int_0^\pi \cos(4\theta)/(1+\cos^2\theta)\,d\theta\)