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Find 
limtan^(2)(theta)[1-sin(theta)].

theta rarr(pi)/(2)
Choose 1 answer:
(A) 0
(B) 
(1)/(2)
(C) -2
(D) The limit doesn't exist

Find limθπ2tan2(θ)[1sin(θ)] \lim_{\theta \rightarrow \frac{\pi}{2}} \tan ^{2}(\theta)[1-\sin (\theta)] .\newlineChoose 11 answer:\newline(A) 00\newline(B) 12 \frac{1}{2} \newline(C) 2-2\newline(D) The limit doesn't exist

Full solution

Q. Find limθπ2tan2(θ)[1sin(θ)] \lim_{\theta \rightarrow \frac{\pi}{2}} \tan ^{2}(\theta)[1-\sin (\theta)] .\newlineChoose 11 answer:\newline(A) 00\newline(B) 12 \frac{1}{2} \newline(C) 2-2\newline(D) The limit doesn't exist
  1. Identify Behavior: Identify the behavior of the function as θ\theta approaches π2\frac{\pi}{2}. As θ\theta approaches π2\frac{\pi}{2}, sin(θ)\sin(\theta) approaches 11. This means that the term (1sin(θ))(1 - \sin(\theta)) approaches 00. However, tan(θ)\tan(\theta) approaches infinity as θ\theta approaches π2\frac{\pi}{2} from the left, and negative infinity from the right, because π2\frac{\pi}{2}11 and π2\frac{\pi}{2}22 approaches 00. The square of tan(θ)\tan(\theta), which is π2\frac{\pi}{2}55, will approach positive infinity from both sides since squaring a negative number results in a positive number. We have an indeterminate form of type π2\frac{\pi}{2}66, which means we need to manipulate the expression to resolve the indeterminate form.
  2. Apply L'Hôpital's Rule: Apply L'Hôpital's Rule to resolve the indeterminate form.\newlineL'Hôpital's Rule states that if the limit of f(θ)/g(θ)f(\theta)/g(\theta) as θ\theta approaches a value cc is of the form 0/00/0 or /\infty/\infty, then the limit of f(θ)/g(θ)f(\theta)/g(\theta) as θ\theta approaches cc is the same as the limit of f(θ)/g(θ)f'(\theta)/g'(\theta) as θ\theta approaches cc, provided that the derivatives exist and the limit of f(θ)/g(θ)f'(\theta)/g'(\theta) is determinate.\newlineTo apply L'Hôpital's Rule, we need to rewrite the expression in a form that allows us to use the rule. We can rewrite θ\theta22 as θ\theta33 and then as θ\theta44. To use L'Hôpital's Rule, we need a fraction, so we can set θ\theta55 and θ\theta66. Now we have θ\theta77.
  3. Differentiate Functions: Differentiate f(θ)f(\theta) and g(θ)g(\theta) with respect to θ\theta. The derivative of f(θ)=[sin(θ)]2(1sin(θ))f(\theta) = [\sin(\theta)]^2 * (1 - \sin(\theta)) is f(θ)=2sin(θ)cos(θ)(1sin(θ))[sin(θ)]2cos(θ)f'(\theta) = 2\sin(\theta)\cos(\theta) * (1 - \sin(\theta)) - [\sin(\theta)]^2 * \cos(\theta) using the product rule and chain rule. The derivative of g(θ)=cos2(θ)g(\theta) = \cos^2(\theta) is g(θ)=2cos(θ)sin(θ)g'(\theta) = -2\cos(\theta)\sin(\theta) using the chain rule.
  4. Apply L'Hôpital's Rule Correction: Apply L'Hôpital's Rule by taking the limit of f(θ)/g(θ)f'(\theta)/g'(\theta) as θ\theta approaches π/2\pi/2. We now take the limit of f(θ)/g(θ)f'(\theta)/g'(\theta) as θ\theta approaches π/2\pi/2. However, there is a mistake in the differentiation process in the previous step. The correct derivative of f(θ)f(\theta) should be f(θ)=2sin(θ)cos(θ)(1sin(θ))[sin(θ)]2cos(θ)=2sin(θ)cos(θ)2sin2(θ)cos(θ)[sin(θ)]2cos(θ)f'(\theta) = 2\sin(\theta)\cos(\theta) \cdot (1 - \sin(\theta)) - [\sin(\theta)]^2 \cdot \cos(\theta) = 2\sin(\theta)\cos(\theta) - 2\sin^2(\theta)\cos(\theta) - [\sin(\theta)]^2 \cdot \cos(\theta). We need to correct this before proceeding.

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