About probability, math people help me please

Express the following as a function of a single angle, cos(60) cos(-20) - sin(60) sin(-20)

Aright triangle has an area of 18 square inches. b: if the triangle is not an isosceles triangle, what are all the possible lengths of the legs, if the lengths are whole numbers. answer !

The fraction of defective integrated circuits produced in a photolithography process is being studied. a random sample of 300 circuits is tested, revealing 17 defectives. (a) calculate a 95% two-sided confidence interval on the fraction of defective circuits produced by this particular tool. round the answers to 4 decimal places. less-than-or-equal-to p less-than-or-equal-to (b) calculate a 95% upper confidence bound on the fraction of defective circuits. round the answer to 4 decimal places. p less-than-or-equal-to