If tan α equals the integral solution of
the inequality 4x^2 −16x+15<0 and
cos β equals to the slope of the bisector
of the first quadrant, then
sin (α+β) sin (α−β) is equal to
If the ratio of the students that pass a test to those that fail is in ratio 4:1,
If 9 students were chosen at random, what is the probability that exactly
7 passed the test.