find dy/dx implicitly and find the largest interval of the form −a < y < a or 0 < y < a such that y is a differentiable function of x. tan y = x

When amy exercises in her fitness center for 1 hr she burns a total of 475 calories.if she burns 9 calories a minute jogging on the treadmill and then burns 6.5 calories a minute pedaling on the stationary bicycle how many minutes of the hour does she spend exercising on the bicycle?