Chapter 1: Problem 45
Solve the following equations. $$\sin \theta \cos \theta=0,0 \leq \theta<2 \pi$$
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Chapter 1: Problem 45
Solve the following equations. $$\sin \theta \cos \theta=0,0 \leq \theta<2 \pi$$
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Prove the following identities. $$\cos ^{-1} x+\cos ^{-1}(-x)=\pi$$
Determine whether the following statements are true and give an explanation or counterexample. a. The range of \(f(x)=2 x-38\) is all real numbers. b. The relation \(f(x)=x^{6}+1\) is not a function because \(f(1)=f(-1)=2\) c. If \(f(x)=x^{-1},\) then \(f(1 / x)=1 / f(x)\) d. In general, \(f(f(x))=(f(x))^{2}\) e. In general, \(f(g(x))=g(f(x))\) f. In general, \(f(g(x))=(f \circ g)(x)\) g. If \(f(x)\) is an even function, then \(c f(a x)\) is an even function, where \(a\) and \(c\) are real numbers. h. If \(f(x)\) is an odd function, then \(f(x)+d\) is an odd function, where \(d\) is a real number. i. If \(f\) is both even and odd, then \(f(x)=0\) for all \(x\)
Consider the quartic polynomial \(y=f(x)=x^{4}-x^{2}\). a. Graph \(f\) and estimate the largest intervals on which it is one-to-one. The goal is to find the inverse function on each of these intervals. b. Make the substitution \(u=x^{2}\) to solve the equation \(y=f(x)\) for \(x\) in terms of \(y .\) Be sure you have included all possible solutions. c. Write each inverse function in the form \(y=f^{-1}(x)\) for each of the intervals found in part (a).
Finding the inverse of a cubic polynomial is equivalent to solving a cubic equation. A special case that is simpler than the general case is the cubic \(y=f(x)=x^{3}+a x\). Find the inverse of the following cubics using the substitution (known as Vieta's substitution) \(x=z-a /(3 z) .\) Be sure to determine where the function is one-to-one. $$f(x)=x^{3}-2 x$$
(Torricelli's law) A cylindrical tank with a cross-sectional area of \(100 \mathrm{cm}^{2}\) is filled to a depth of \(100 \mathrm{cm}\) with water. At \(t=0,\) a drain in the bottom of the tank with an area of \(10 \mathrm{cm}^{2}\) is opened, allowing water to flow out of the tank. The depth of water in the tank at time \(t \geq 0\) is \(d(t)=(10-2.2 t)^{2}\) a. Check that \(d(0)=100,\) as specified. b. At what time is the tank empty? c. What is an appropriate domain for \(d ?\)
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