(a) A, B,C, D are the four interior angles, taken in order, of a cyclic quadrilateral. Prove that: cot(A) + cot(B) + cot(C) + cot(D) = 0.

(b) If cos(x) + sin(x) = m and sec(x) + cosec(x) = n, prove that n(m^2- 1) = 2m.

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Abox of chocolates costs $7. which equation relates the number of boxes sold (x) and total cost of the boxes sold (y)?

Given the equation y − 4 = three fourths(x + 8) in point-slope form, identify the equation of the same line in standard form. −three fourthsx + y = 10 3x − 4y = −40 y = three fourthsx + 12 y = three fourthsx + 10

The management of a supermarket wants to adopt a new promotional policy of giving a free gift to every customer who spends more than a certain amount per visit at this supermarket. the expectation of the management is that after this promotional policy is advertised, the expenditures for all customers at this supermarket will be normally distributed with a mean of $95 and a standard deviation of $20. if the management wants to give free gifts to at most 10% of the customers, what should the amount be above which a customer would receive a free gift?