Trig derivatives are used to find rates of change for sine, cosine, tangent, cotangent, secant, and cosecant functions. The six basic trig derivative rules are important to memorize because they show up often in Calculus 1. These practice problems include constant multiples, basic trig derivatives, chain rule variations, and products involving trig functions.
Notes

Practice Problems
\(\textbf{1)}\) \(f(x)=5\sec x\)
The derivative is \(f'(x)=5 \tan x \sec x\)
\(\,\,\,\,\,\,f(x)=5\sec x\)
\(\,\,\,\,\,\,\frac{d}{dx}\left(\sec x\right)=\sec x\tan x\)
\(\,\,\,\,\,\,f'(x)=5\sec x\tan x\)
\(\,\,\,\,\,\)The derivative is \(f'(x)=5 \tan x \sec x\)
\(\textbf{2)}\) \(f(x)=5\cot x\)
The derivative is \(f'(x)=-5 \csc^2 x\)
\(\,\,\,\,\,\,f(x)=5\cot x\)
\(\,\,\,\,\,\,\frac{d}{dx}\left(\cot x\right)=-\csc^2 x\)
\(\,\,\,\,\,\,f'(x)=5\left(-\csc^2 x\right)\)
\(\,\,\,\,\,\)The derivative is \(f'(x)=-5 \csc^2 x\)
\(\textbf{3)}\) \(f(x)=5 \csc x\)
The derivative is \(f'(x)=-5\cot x \csc x\)
\(\,\,\,\,\,\,f(x)=5\csc x\)
\(\,\,\,\,\,\,\frac{d}{dx}\left(\csc x\right)=-\csc x\cot x\)
\(\,\,\,\,\,\,f'(x)=5\left(-\csc x\cot x\right)\)
\(\,\,\,\,\,\)The derivative is \(f'(x)=-5\cot x \csc x\)
\(\textbf{4)}\) \(f(x)=5 \tan x\)
The derivative is \(f'(x)=5\sec^2 x\)
\(\,\,\,\,\,\,f(x)=5\tan x\)
\(\,\,\,\,\,\,\frac{d}{dx}\left(\tan x\right)=\sec^2 x\)
\(\,\,\,\,\,\,f'(x)=5\sec^2 x\)
\(\,\,\,\,\,\)The derivative is \(f'(x)=5\sec^2 x\)
\(\textbf{5)}\) \(f(x)=5 \sin x\)
The derivative is \(f'(x)=5 \cos x\)
\(\,\,\,\,\,\,f(x)=5\sin x\)
\(\,\,\,\,\,\,\frac{d}{dx}\left(\sin x\right)=\cos x\)
\(\,\,\,\,\,\,f'(x)=5\cos x\)
\(\,\,\,\,\,\)The derivative is \(f'(x)=5 \cos x\)
\(\textbf{6)}\) \(f(x)=5 \cos x\)
The derivative is \(f'(x)=-5 \sin x\)
\(\,\,\,\,\,\,f(x)=5\cos x\)
\(\,\,\,\,\,\,\frac{d}{dx}\left(\cos x\right)=-\sin x\)
\(\,\,\,\,\,\,f'(x)=5\left(-\sin x\right)\)
\(\,\,\,\,\,\)The derivative is \(f'(x)=-5 \sin x\)
\(\textbf{7)}\) \(f(x)=7\sec x\)
The derivative is \(f'(x)=7 \tan x \sec x\)
\(\,\,\,\,\,\,f(x)=7\sec x\)
\(\,\,\,\,\,\,\frac{d}{dx}\left(\sec x\right)=\sec x\tan x\)
\(\,\,\,\,\,\,f'(x)=7\sec x\tan x\)
\(\,\,\,\,\,\)The derivative is \(f'(x)=7 \tan x \sec x\)
\(\textbf{8)}\) \(f(x)=3 \cot x\)
The derivative is \(f'(x)=-3\csc^2 x\)
\(\,\,\,\,\,\,f(x)=3\cot x\)
\(\,\,\,\,\,\,\frac{d}{dx}\left(\cot x\right)=-\csc^2 x\)
\(\,\,\,\,\,\,f'(x)=3\left(-\csc^2 x\right)\)
\(\,\,\,\,\,\)The derivative is \(f'(x)=-3\csc^2 x\)
\(\textbf{9)}\) \(f(x)=7 \csc x\)
The derivative is \(f'(x)=-7\cot x \csc x\)
\(\,\,\,\,\,\,f(x)=7\csc x\)
\(\,\,\,\,\,\,\frac{d}{dx}\left(\csc x\right)=-\csc x\cot x\)
\(\,\,\,\,\,\,f'(x)=7\left(-\csc x\cot x\right)\)
\(\,\,\,\,\,\)The derivative is \(f'(x)=-7\cot x \csc x\)
\(\textbf{10)}\) \(f(x)=4\sin x-2\cos x\)
The derivative is \(f'(x)=4\cos x+2\sin x\)
\(\,\,\,\,\,\,f(x)=4\sin x-2\cos x\)
\(\,\,\,\,\,\,\frac{d}{dx}\left(\sin x\right)=\cos x\)
\(\,\,\,\,\,\,\frac{d}{dx}\left(\cos x\right)=-\sin x\)
\(\,\,\,\,\,\,f'(x)=4\cos x-2\left(-\sin x\right)\)
\(\,\,\,\,\,\)The derivative is \(f'(x)=4\cos x+2\sin x\)
\(\textbf{11)}\) \(f(x)=6\tan x+5\sec x\)
The derivative is \(f'(x)=6\sec^2 x+5\sec x\tan x\)
\(\,\,\,\,\,\,f(x)=6\tan x+5\sec x\)
\(\,\,\,\,\,\,\frac{d}{dx}\left(\tan x\right)=\sec^2 x\)
\(\,\,\,\,\,\,\frac{d}{dx}\left(\sec x\right)=\sec x\tan x\)
\(\,\,\,\,\,\,f'(x)=6\sec^2 x+5\sec x\tan x\)
\(\,\,\,\,\,\)The derivative is \(f'(x)=6\sec^2 x+5\sec x\tan x\)
\(\textbf{12)}\) \(f(x)=3\csc x-8\cot x\)
The derivative is \(f'(x)=-3\csc x\cot x+8\csc^2 x\)
\(\,\,\,\,\,\,f(x)=3\csc x-8\cot x\)
\(\,\,\,\,\,\,\frac{d}{dx}\left(\csc x\right)=-\csc x\cot x\)
\(\,\,\,\,\,\,\frac{d}{dx}\left(\cot x\right)=-\csc^2 x\)
\(\,\,\,\,\,\,f'(x)=3\left(-\csc x\cot x\right)-8\left(-\csc^2 x\right)\)
\(\,\,\,\,\,\)The derivative is \(f'(x)=-3\csc x\cot x+8\csc^2 x\)
\(\textbf{13)}\) \(f(x)=\sin(4x)\)
The derivative is \(f'(x)=4\cos(4x)\)
\(\,\,\,\,\,\,f(x)=\sin(4x)\)
\(\,\,\,\,\,\,\text{Use the chain rule.}\)
\(\,\,\,\,\,\,u=4x\)
\(\,\,\,\,\,\,u’=4\)
\(\,\,\,\,\,\,f'(x)=\cos(4x)\cdot 4\)
\(\,\,\,\,\,\)The derivative is \(f'(x)=4\cos(4x)\)
\(\textbf{14)}\) \(f(x)=\cos(3x^2)\)
The derivative is \(f'(x)=-6x\sin(3x^2)\)
\(\,\,\,\,\,\,f(x)=\cos(3x^2)\)
\(\,\,\,\,\,\,\text{Use the chain rule.}\)
\(\,\,\,\,\,\,u=3x^2\)
\(\,\,\,\,\,\,u’=6x\)
\(\,\,\,\,\,\,f'(x)=-\sin(3x^2)\cdot 6x\)
\(\,\,\,\,\,\)The derivative is \(f'(x)=-6x\sin(3x^2)\)
\(\textbf{15)}\) \(f(x)=\tan(5x)\)
The derivative is \(f'(x)=5\sec^2(5x)\)
\(\,\,\,\,\,\,f(x)=\tan(5x)\)
\(\,\,\,\,\,\,\text{Use the chain rule.}\)
\(\,\,\,\,\,\,u=5x\)
\(\,\,\,\,\,\,u’=5\)
\(\,\,\,\,\,\,f'(x)=\sec^2(5x)\cdot 5\)
\(\,\,\,\,\,\)The derivative is \(f'(x)=5\sec^2(5x)\)
\(\textbf{16)}\) \(f(x)=\sec(x^2+1)\)
The derivative is \(f'(x)=2x\sec(x^2+1)\tan(x^2+1)\)
\(\,\,\,\,\,\,f(x)=\sec(x^2+1)\)
\(\,\,\,\,\,\,\text{Use the chain rule.}\)
\(\,\,\,\,\,\,u=x^2+1\)
\(\,\,\,\,\,\,u’=2x\)
\(\,\,\,\,\,\,f'(x)=\sec(x^2+1)\tan(x^2+1)\cdot 2x\)
\(\,\,\,\,\,\)The derivative is \(f'(x)=2x\sec(x^2+1)\tan(x^2+1)\)
\(\textbf{17)}\) \(f(x)=x^2\sin x\)
The derivative is \(f'(x)=x^2\cos x+2x\sin x\)
\(\,\,\,\,\,\,f(x)=x^2\sin x\)
\(\,\,\,\,\,\,\text{Use the product rule.}\)
\(\,\,\,\,\,\,f'(x)=x^2(\sin x)’+(x^2)’\sin x\)
\(\,\,\,\,\,\,f'(x)=x^2\cos x+2x\sin x\)
\(\,\,\,\,\,\)The derivative is \(f'(x)=x^2\cos x+2x\sin x\)
\(\textbf{18)}\) \(f(x)=e^x\cos x\)
The derivative is \(f'(x)=e^x\cos x-e^x\sin x\)
\(\,\,\,\,\,\,f(x)=e^x\cos x\)
\(\,\,\,\,\,\,\text{Use the product rule.}\)
\(\,\,\,\,\,\,f'(x)=e^x(\cos x)’+(e^x)’\cos x\)
\(\,\,\,\,\,\,f'(x)=e^x(-\sin x)+e^x\cos x\)
\(\,\,\,\,\,\)The derivative is \(f'(x)=e^x\cos x-e^x\sin x\)
\(\textbf{19)}\) \(f(x)=\ln x \tan x\)
The derivative is \(f'(x)=\ln x\sec^2 x+\frac{\tan x}{x}\)
\(\,\,\,\,\,\,f(x)=\ln x \tan x\)
\(\,\,\,\,\,\,\text{Use the product rule.}\)
\(\,\,\,\,\,\,f'(x)=\ln x(\tan x)’+(\ln x)’\tan x\)
\(\,\,\,\,\,\,f'(x)=\ln x\sec^2 x+\frac{1}{x}\tan x\)
\(\,\,\,\,\,\)The derivative is \(f'(x)=\ln x\sec^2 x+\frac{\tan x}{x}\)
\(\textbf{20)}\) \(f(x)=\displaystyle\frac{\sin x}{x}\)
The derivative is \(f'(x)=\displaystyle\frac{x\cos x-\sin x}{x^2}\)
\(\,\,\,\,\,\,f(x)=\displaystyle\frac{\sin x}{x}\)
\(\,\,\,\,\,\,\text{Use the quotient rule.}\)
\(\,\,\,\,\,\,f'(x)=\displaystyle\frac{x(\sin x)’-(\sin x)(x)’}{x^2}\)
\(\,\,\,\,\,\,f'(x)=\displaystyle\frac{x\cos x-\sin x}{x^2}\)
\(\,\,\,\,\,\)The derivative is \(f'(x)=\displaystyle\frac{x\cos x-\sin x}{x^2}\)
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