Question 703480
The graph over one period (from x = 0 to x = pi/2) is




{{{ drawing(500, 500, -10, 10, -10, 10,
 graph( 500, 500, -10, 10, -10, 10,0,(1/(cos(4*x + 3.14159265)) - 1)*((sqrt(0.61685 - (x-0.7854)^2))/(sqrt(0.61685 - (x-0.7854)^2))))

)}}}