","comment":{"@type":"Comment","text":" First check the continuity of the function and compare the value of left hand and right-hand limit after that calculate the value of $\\underset{x\\to 1}{\\mathop{\\lim }}\\,$."},"encodingFormat":"text/markdown","suggestedAnswer":[{"@type":"Answer","encodingFormat":"text/html","text":" $$1$$","position":0},{"@type":"Answer","encodingFormat":"text/html","text":" $$4$$","position":2},{"@type":"Answer","encodingFormat":"text/html","text":" None of these ","position":3}],"acceptedAnswer":[{"@type":"Answer","encodingFormat":"text/html","text":" $$2$$","position":1,"answerExplanation":{"@type":"Comment","text":"Clearly, the point of discontinuity from graph is $$x=1$$ $$ \\\\ \\underset{x\\to {{1}^{-}}}{\\mathop{\\lim }}\\,f\\left( x \\right)={{1}^{3}}+1=2 \\\\ \\underset{x\\to {{1}^{+}}}{\\mathop{\\lim }}\\,f\\left( x \\right)=2\\left( 1 \\right)=2 \\\\ $$ Since RHL = LHL, therefore function is continuous and the value of $$\\underset{x\\to 1}{\\mathop{\\lim }}\\,=2$$.","encodingFormat":"text/html"},"comment":{"@type":"Comment"}}]},{"@type":"Question","eduQuestionType":"Multiple choice","learningResourceType":"Practice problem","educationalLevel":"beginner","name":"Estimating limit values from graphs Quiz 1","text":" If function $$f(x)=\\left\\{ \\begin{matrix} x,x\\le \\dfrac{3-\\sqrt{5}}{2} \\\\ {{(x-1)}^{2}},x>\\dfrac{3-\\sqrt{5}}{2} \\\\ \\end{matrix} \\right.$$, then find $$\\underset{x\\to \\frac{3-\\sqrt{5}}{2}}{\\mathop{\\lim }}\\,f(x)$$ ","comment":{"@type":"Comment","text":" From graph find the point of discontinuity and then check the right hand and left-hand side limit of the function to find $\\underset{x\\to \\frac{3-\\sqrt{5}}{2}}{\\mathop{\\lim }}\\,f\\left( x \\right)$."},"encodingFormat":"text/markdown","suggestedAnswer":[{"@type":"Answer","encodingFormat":"text/html","text":" $$\\dfrac{3+\\sqrt{5}}{2}$$ ","position":1},{"@type":"Answer","encodingFormat":"text/html","text":" $$3-\\sqrt{5}$$","position":2},{"@type":"Answer","encodingFormat":"text/html","text":" $$3+\\sqrt{5}$$ ","position":3}],"acceptedAnswer":[{"@type":"Answer","encodingFormat":"text/html","text":" $$\\dfrac{3-\\sqrt{5}}{2}$$","position":0,"answerExplanation":{"@type":"Comment","text":"$$x=\\dfrac{3-\\sqrt{5}}{2}$$ $$($$Point of discontinuity$$)$$ $$ \\\\ \\Rightarrow x\\text{ = }\\dfrac{3-2.236}{2}=0.382 \\\\ $$ Clearly from graph $$\\underset{x\\to \\frac{3-\\sqrt{5}}{2}}{\\mathop{\\lim }}\\,f\\left( x \\right)$$ value is less than $$\\text{0}\\text{.5}$$ approximately is equal to $$x$$ which is $$\\dfrac{3-\\sqrt{5}}{2}$$","encodingFormat":"text/html"},"comment":{"@type":"Comment"}}]},{"@type":"Question","eduQuestionType":"Multiple choice","learningResourceType":"Practice problem","educationalLevel":"beginner","name":"Estimating limit values from graphs Quiz 1","text":" If function $$f(x)=\\left\\{ \\begin{matrix} 3x,x\\le \\sqrt{2}-1 \\\\ {{x}^{3}}+{{x}^{2}}+1,x>\\sqrt{2}-1 \\\\ \\end{matrix} \\right.$$, then find $$\\underset{x\\to \\sqrt{2}-1}{\\mathop{\\lim }}\\,f(x)$$ .
","comment":{"@type":"Comment","text":" Analyse the graph to find $\\underset{x\\to \\sqrt{2}-1}{\\mathop{\\lim }}\\,$ . Compare the right-hand side and left side limit to check discontinuity of function and then calculate the limit."},"encodingFormat":"text/markdown","suggestedAnswer":[{"@type":"Answer","encodingFormat":"text/html","text":" $$\\sqrt{2}-1$$ ","position":0},{"@type":"Answer","encodingFormat":"text/html","text":" $$2(\\sqrt{2}-1)$$ ","position":1},{"@type":"Answer","encodingFormat":"text/html","text":" $$4(\\sqrt{2}-1)$$","position":3}],"acceptedAnswer":[{"@type":"Answer","encodingFormat":"text/html","text":" $$3(\\sqrt{2}-1)$$","position":2,"answerExplanation":{"@type":"Comment","text":"From the graph $$x=\\sqrt{2}-1=0.414$$ is a point of discontinuity. $$ \\\\ $$ The limit $$\\underset{x\\to \\sqrt{2}-1}{\\mathop{\\lim }}\\,f\\left( x \\right)$$ as seen from graph can be seen to be $$\\text{1}\\text{.2}$$. $$ \\\\ $$ From the options the limit can be $$a\\left( \\sqrt{2}-1 \\right)$$ $$\\left( a=\\text{constant} \\right)$$ $$ \\\\ \\Rightarrow a\\left( \\sqrt{2}-1 \\right)=1.2 \\\\ \\Rightarrow a=\\dfrac{1.2}{0.414} \\\\ \\Rightarrow a=2.89\\simeq 3 \\\\ $$ Therefore, $$\\underset{x\\to \\sqrt{2}-1}{\\mathop{\\lim }}\\,f\\left( x \\right)=3\\left( \\sqrt{2}-1 \\right)$$","encodingFormat":"text/html"},"comment":{"@type":"Comment"}}]},{"@type":"Question","eduQuestionType":"Multiple choice","learningResourceType":"Practice problem","educationalLevel":"beginner","name":"Estimating limit values from graphs Quiz 1","text":" If function $$f(x)=\\left\\{ \\begin{matrix} {{x}^{2}}-6x+2,x\\le \\dfrac{3-\\sqrt{5}}{2} \\\\ -{{x}^{2}},x>\\dfrac{3-\\sqrt{5}}{2} \\\\\\end{matrix} \\right.$$, then find $$\\underset{x\\to \\frac{3-\\sqrt{5}}{2}}{\\mathop{\\lim }}\\,f(x)$$
","comment":{"@type":"Comment","text":" First from the graph analyse the value of the limit and then we can directly check the options and see from which it is closest to the value obtained by the graph."},"encodingFormat":"text/markdown","suggestedAnswer":[{"@type":"Answer","encodingFormat":"text/html","text":" $$\\dfrac{3\\sqrt{5}-3}{2}$$","position":0},{"@type":"Answer","encodingFormat":"text/html","text":" $$\\dfrac{3\\sqrt{5}-5}{2}$$","position":1},{"@type":"Answer","encodingFormat":"text/html","text":" $$\\dfrac{3\\sqrt{5}-9}{2}$$","position":3}],"acceptedAnswer":[{"@type":"Answer","encodingFormat":"text/html","text":" $$\\dfrac{3\\sqrt{5}-7}{2}$$","position":2,"answerExplanation":{"@type":"Comment","text":"From the graph, $$x=\\dfrac{3-\\sqrt{5}}{2}$$ is a point of importance. $$ \\\\ $$ The value of $$\\underset{x\\to \\frac{3-\\sqrt{5}}{2}}{\\mathop{\\lim }}\\,f\\left( x \\right)$$ from graph can be seen to be around $$-0.2$$ and then using this to find the limit. $$ \\\\ $$ Now check the options which is nearly equal to $$-0.2$$ that is $$\\dfrac{3\\sqrt{5}-7}{2}$$ $$ \\\\ $$ So, $$\\Rightarrow \\underset{x\\to \\frac{3-\\sqrt{5}}{2}}{\\mathop{\\lim }}\\,f\\left( x \\right)=\\dfrac{3\\sqrt{5}-7}{2}\\simeq -0.2$$","encodingFormat":"text/html"},"comment":{"@type":"Comment"}}]},{"@type":"Question","eduQuestionType":"Multiple choice","learningResourceType":"Practice problem","educationalLevel":"beginner","name":"Estimating limit values from graphs Quiz 1","text":" If function $$f(x)=\\left\\{ \\begin{matrix} 2{{x}^{3}}-3{{x}^{2}}+2x-1,x\\le 1 \\\\ x-1,x>1 \\\\ \\end{matrix} \\right.$$, then find $$\\underset{x\\to 1}{\\mathop{\\lim }}\\,f(x)$$ .
","comment":{"@type":"Comment","text":" First find the right hand and left-hand limit of the function and then check if they are equal for their continuity and then the required value is the limit for the function."},"encodingFormat":"text/markdown","suggestedAnswer":[{"@type":"Answer","encodingFormat":"text/html","text":" $$1$$","position":1},{"@type":"Answer","encodingFormat":"text/html","text":" $$2$$","position":2},{"@type":"Answer","encodingFormat":"text/html","text":" None of the above ","position":3}],"acceptedAnswer":[{"@type":"Answer","encodingFormat":"text/html","text":" $$0$$","position":0,"answerExplanation":{"@type":"Comment","text":" From graph the function changes at $$x=1$$ which the value of function is $$f\\left( 1 \\right)=0$$ $$ \\\\ $$ So, the limit of function as $$x\\to 1$$ is $$\\underset{x\\to 1}{\\mathop{\\lim }}\\,f(x)=0$$ $$ \\\\ $$ Check the above value from LHL and RHL $$ \\\\ \\Rightarrow \\underset{x\\to {{1}^{-}}}{\\mathop{\\lim }}\\,f\\left( x \\right)=2{{x}^{3}}-3{{x}^{2}}+2x \\\\ =2\\times {{1}^{3}}-3\\times {{1}^{2}}+2\\times 1 =0 \\\\ \\Rightarrow \\underset{x\\to {{1}^{+}}}{\\mathop{\\lim }}\\,f\\left( x \\right)=x-1 =1-1 =0 \\\\ $$ Clearly, RHL = LHL, therefore the function is continuous and the limit at $$x=1$$ is $$\\text{0}$$.","encodingFormat":"text/html"},"comment":{"@type":"Comment"}}]}]}