30 POINTS!! On a given workday, the rate, in tons per hour, at which unprocessed ore arrives at a refinery is modeled by O(t) = 20 + 10 cos (t^2/25), where t is measured in hours and 0 ≤ t ≤ 10.

Answerinterviewing there is no image showing, but i believe this is correct/// plz check first.good luck

You need to figure out at which x-value does the graph has a tangent line slope of -1.remember, the derivative is the slope of the tangent line. so find the derivative function and set it to equal -1 to find the x-value that will have a tangent line slope of 0.differentiate with the chain rule.    set the derivative to equal -1 and solve for x.      take log base 10 of both sides. also recall that  .    so the x-coord of the point of tangency is .the y-coordinate of this point of tangency can be calculated using the original function:     using point-slope form, the equation of the tangent line is      the x-intercept of this tangent line is when the graph is at y=0.    this rounds off to  .choice c.