John,

It's been a while (20 years) since I took calculus, but I'm pretty sure
the slope of a sine wave at the zero crossing is +-1.

What value do you believe the slope to be?



John Popelish wrote:
James W wrote:

at the 90deg point, the I curve is crossing the zero point. It's a sine
wave. Sine waves of amplitude 1 have a slope of 1 at the zero crossing, no?


No. If the period is 1 and the peak to peak amplitude is 1, the only
way the slope could be 1 would be if it were a saw tooth wave.