- #1

karush

Gold Member

MHB

- 3,269

- 5

$y=\cos(\tan(5t-4))\\$

chain rule $u=\tan(5t-4)$

$\frac{d}{du}\cos{(u)} \frac{d}{dt}\tan{\left(5t-4\right)}\\$

then

$-\sin{\left (u \right )}\cdot 5 \sec^{2}{\left (5 t - 4 \right )}\\$

replacing u with $\tan(5t-4)$

$-\sin{(\tan(5t-4))}\cdot 5 \sec^{2}{(5t-4)}\\$

$W\vert A$ returns

$-5\sec^2(5t-4)\sin(\tan(5t-4))$

ok I got confused on this u substitution thing but still seems to match the $W\vert A$ return