\(\displaystyle f(x) \ = \ sin\bigg(\frac{3\pi x}{2}\bigg) \ at \ x \ =4, \ y \ = \ 0.\)
\(\displaystyle f \ ' \ (x) \ = \ \frac{3\pi}{2}cos\bigg(\frac{3\pi x}{2}\bigg).\)
\(\displaystyle f \ ' \ (4) \ = \ \frac{3\pi}{2} \ = \ m\)
\(\displaystyle Ergo, \ y-0 \ = \ \frac{3\pi}{2}(x-4) \ = \ \frac{3\pi x}{2}-6\pi\)
\(\displaystyle See \ graph \ below.\)
[attachment=0:r0ig6zqg]xyz.jpg[/attachment:r0ig6zqg]