4. Prove: If x {0, 1} then x² - -x=0. 5. 6. Prove by contrapositive: Suppose x is a real number. If x>0 then x + 16 0. Prove by contradiction: Suppose n is an integer. Then n² - n+10. Hint: You might try organizing the proof by cases on whether n is even or odd. Is n² - n+1 even or odd?

Use the method of reduction of order to find a second solution to ty"-(4t+4)+(4t+8)y = 0, t> 0 Given y₁(t) = e²t Y2(t) = Give your answer in simplest form (ie no coefficients)

1. Suppose the domain of discourse is kinds of minerals. Let A be kinds of minerals that dissolve in acid, let S be minerals that can be scratched by an iron nail, and let C be minerals that are clear. Write expressions using set operations that represent the following sets of minerals: (a) Minerals that dissolve in acid and can be scratched by an iron nail. (b) Minerals that dissolve in acid and are not clear. (c) Minerals that are either clear or both dissolve in acid but cannot be scratched by an iron nail. (d) Minerals that are neither dissolvable in acid nor scratable by an iron nail. (e) Minerals that are either both dissolvable in acid and scratchable by an iron nail or both dissolvable in acid and not clear.

(i) For a given constant a > 0, let an investor's preference be represented by the Gaussian utility function U(w)=1-e-aw² For what range of wealth level w will the investor be non-satiated and risk-averse? Explain your answer. (ii) Give an example of a utility function that exhibits DARA and verify it. (iii) Determine the class of utility functions with relative risk aversion coefficient R(w)= w², w> 0.

Sara (a 23 year old college graduate) is starting her first career.  She met with a financial planner and has determined that she wants $1,000,000 when she retires at the age of 63.  She has found an annuity that pays 4.25%, compounded quarterly. What will she need to save each month, if Sara waits 20 years to start saving?               N:                           P/Y:             I%:                         C/Y:             PMT:                              FV:     End or Begin $4158.98 $4,115.26 $2645.83 $6,707.40

Sara (a 23 year old college graduate) is starting her first career.  She met with a financial planner and has determined that she wants $1,000,000 when she retires at the age of 63.  She has found an annuity that pays 4.25%, compounded quarterly. What will she need to save each month, if a) Sara begins saving now?               N:                           P/Y:             I%:                         C/Y:             PMT:                              FV:     End or Begin $1,323.80 $1,376.59 $794.74 $1,000,000

The entire graph of the function g is shown in the figure below. Write the domain and range of g as intervals or unions of intervals. 5 4 -3. 2 3 omain = range ☐ =

Can you prove this integral equation?Note: It also has an application to prove that 22/7 > π.

1. The number of claims is modelled by a NB2(n, p) (the number of fail- ures before the nth success with probability p of success). The sample x = (x1, x2,,XN) with N = 100 returns N N xj = 754, Σε = 70425. j=1 Estimate the parameters n and p using the point estimates. [5 Marks]