Question

How do you find the 50th derivative of y=cos(x)y=cos(x) ?

Answer 1

$y=cosx\\\\y'=-sinx\\\\y''=-cosx\\\\y'''=-(-sinx)=sinx\\\\y''''=cosx\to again\ this\ same...\\\\50:4=12+(R=2)\\\\50th\ derivate\ of\ y=cosx\ is\ equal\ y''=-cosx$