We want to find the derivative. We can see that we have two thetas, so we're going to have to use the product rule. In case we don't remember what the derivative of the hyperbolic inverse tangent is, think about letting F of X be the hyperbolic tangent of X. So F inverse of X is the hyperbolic tangent inverse of X. So we know by the definition F inverse the derivative of X is 1 divided by the derivative of the original function, the derivative of hyperbolic tangent as hyperbolic secant squared with the F inverse of X going in. Now we also remember that with hyperbolics we have hyperbolic cosine squared X minus hyperbolic sine squared X equaling 1. So we need the relationship with hyperbolic secant. So we're going to take each of these and divide by hyperbolic cosine, and that's going to give us a new relationship that says 1 minus hyperbolic tangent equal hyperbolic secant. So instead of this hyperbolic secant squared, we're going to put in one minus tangent the hyperbolic tangent of whatever this was. And now the hyperbolic tangent and the tangent hyperbolic inverse are going to cancel, leaving us just an X ^2 down here at the end. So when we do the derivative over here, we're going to have, let's actually multiply it out first. So we get one times hyperbolic tangent of four Theta minus. Oh, let's not multiply out. Let's just use the product rule. So dyd Theta, the derivative of the 1st in this case -4 times the 2nd plus the derivative of the second. This tangent inverse of four Theta is going to give us 1 / 1 minus four Theta squared, but then we have to take the derivative on the inside, so that's times 4, and then that's all getting multiplied by 1 -, 4 Theta. So our dyd Theta is -4 hyperbolic tangent inverse of four Theta. This is going to turn into four 1 - 4 Theta over 1 minus. Oops, that was a plus in here 1 - 16 Theta squared. But this is going to factor so -4 hyperbolic inverse tangent 4 Theta plus four 1 - 4 Theta over 1 - 4 Theta times 1 + 4 Theta. So the 1 - 4 thetas cancel. So we get -4 hyperbolic inverse of tangent 4 Theta plus 4 / 1 + 4 Theta. So there's my 4 / 1 + 4 Theta, and there's my. If I distribute the four out, there's my -4 tangent inverse 4 Theta.