00:01
Okay, so for the first part, we're going to use the quotient rule.
00:04
And in that, what you do is you take the derivative of the numerator, which in this case is 10x minus 1.
00:14
So the derivative of 10x is 2.
00:16
So you get squared x, and then derivative of 1 is 0.
00:21
And then you write the denominator as it is minus the numerator as it is and the derivative of the denominator denominator which is secant x 10 x and this entire thing gets divided by secant squared x and when you simplify and rewrite this final answer is secant x minus 10xx minus 1 into tan x over secant x so that's the first part now if we go to b part another way to solve this is to simplify the given function so this is the given function and we know that tan x is sine x over cosine x minus 1 over secant is 1 over cosine x.
01:41
Now if we separate the terms, you get sine x over, oops, cosine x over 1 over cosine x minus 1 over 1 over cosine x.
02:00
So here the cosines cancel.
02:04
So this is going to equal so sine x minus cosine x.
02:16
And if you take the derivative of that, the derivative of sine is cosine, and the derivative of cosine is minus sine.
02:29
So the final answer is cosine x plus sine x.
02:37
Now to show that part a and part b are actually the same answer, we can try and simplify the answer that we got in part a.
02:47
So let's rewrite what we got in part a, which is second x minus 10x minus 1 into tan x over secant x.
03:07
So let's try and simplify this.
03:12
Let's write the first term as it is...