Differentiate (x2-5x+8)(x3+7x+ 9) in three ways mentioned below

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 Multiple Choice QuestionsShort Answer Type

271.  Differentiate the following w.r.t. x :
xx + xa + ax + aa for some fixed a > 0 and x > 0
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272. Find space dy over dx comma space if space straight y to the power of straight x plus straight x to the power of straight y plus straight x to the power of straight x equals straight a to the power of straight b.
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273. If space straight y equals 1 plus fraction numerator straight c subscript 1 over denominator straight x minus straight c subscript 1 end fraction plus fraction numerator straight c subscript 2 straight x over denominator left parenthesis straight x minus straight c subscript 1 right parenthesis left parenthesis straight x minus straight c subscript 2 right parenthesis end fraction comma space prove space that space
dy over dx equals straight y over straight x open parentheses fraction numerator straight c subscript 1 over denominator straight c subscript 1 minus straight x end fraction plus fraction numerator straight c subscript 2 over denominator straight c subscript 2 minus straight x end fraction close parentheses
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274. If space straight y equals fraction numerator ax over denominator left parenthesis straight x minus straight a right parenthesis left parenthesis straight x minus straight b right parenthesis left parenthesis straight x minus straight c right parenthesis end fraction plus fraction numerator bx over denominator left parenthesis straight x minus straight b right parenthesis left parenthesis straight x minus straight c right parenthesis end fraction plus fraction numerator straight c over denominator straight x minus straight c end fraction plus 1.
prove space that space fraction numerator straight y apostrophe over denominator straight y end fraction equals 1 over straight x open parentheses fraction numerator straight a over denominator straight a minus straight x end fraction plus fraction numerator straight b over denominator straight b minus straight x end fraction plus fraction numerator straight c over denominator straight c minus straight x end fraction close parentheses
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275. If u, v, w are differentiable function ofx, then show that
straight d over dx left parenthesis straight u. straight v. straight w right parenthesis equals du over dx. vw plus straight u. dv over dx. straight w plus straight u. straight v dw over dx
in two ways - first by repeated application of product rule, second by logarithmic differentiation.
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276.

Differentiate (x2-5x+8)(x3+7x+ 9) in three ways mentioned below :
(i) by using product rule.
(ii) by expanding the product to obtain a single polynomial.
(iii) by logarithmic differentiation.
Also verify that three answers so obtained are the same.


Let space space space space space space space space space straight y equals left parenthesis straight x squared minus 5 space straight x plus 8 right parenthesis left parenthesis straight x cubed plus 7 straight x plus 9 right parenthesis
left parenthesis straight i right parenthesis therefore space dy over dx equals left parenthesis straight x squared minus 5 space straight x plus 8 right parenthesis. straight d over dx left parenthesis straight x cubed plus 7 straight x plus 9 right parenthesis plus left parenthesis straight x cubed plus 7 straight x plus 9 right parenthesis. straight d over dx left parenthesis straight x squared minus 5 space straight x plus 8 right parenthesis
space space space space space space equals left parenthesis straight x squared minus 5 space straight x plus 8 right parenthesis left parenthesis 3 straight x squared plus 7 right parenthesis plus left parenthesis straight x cubed plus 7 straight x plus 9 right parenthesis left parenthesis 2 straight x minus 5 right parenthesis
space space space space space space equals 3 straight x to the power of 4 plus 7 straight x squared minus 15 straight x cubed minus 35 straight x plus 24 straight x squared plus 56 plus 2 straight x to the power of 4 minus 5 straight x cubed plus 14 straight x squared minus 35 straight x plus 18 straight x minus 45
space space space space space space equals 5 straight x to the power of 4 minus 20 straight x cubed plus 45 straight x squared minus 5 straight x minus 52 straight x plus 11
left parenthesis ii right parenthesis space space space space space space space space space space space straight y equals straight x to the power of 5 minus 5 straight x to the power of 4 plus 15 straight x cubed minus 26 straight x squared plus 11 straight x plus 72
therefore 1 over straight y dy over dx equals 5 straight x to the power of 4 minus 20 straight x 3 plus 45 straight x squared minus 52 straight x plus 11
left parenthesis iii right parenthesis space space space space log space straight y equals log left parenthesis straight x squared minus 5 space straight x plus 8 right parenthesis plus log left parenthesis straight x cubed plus 7 straight x plus 9 right parenthesis
therefore space 1 over straight y dy over dx equals fraction numerator 2 straight x minus 5 over denominator straight x squared minus 5 space straight x plus 8 end fraction plus fraction numerator 3 straight x squared plus 7 over denominator straight x cubed plus 7 straight x plus 9 end fraction
therefore space space space space space space space dy over dx equals left parenthesis straight x squared minus 5 space straight x plus 8 right parenthesis left parenthesis straight x cubed plus 7 straight x plus 9 right parenthesis open parentheses fraction numerator 2 straight x minus 5 over denominator straight x squared minus 5 space straight x plus 8 end fraction plus fraction numerator 3 straight x squared plus 7 over denominator straight x cubed plus 7 straight x plus 9 end fraction close parentheses
space space space space space space space space space space space space space space space space space space space equals left parenthesis 2 straight x minus 5 right parenthesis left parenthesis straight x cubed plus 7 straight x plus 9 right parenthesis plus left parenthesis 3 straight x squared plus 7 right parenthesis left parenthesis straight x squared minus 5 space straight x plus 8 right parenthesis
space space space space space space space space space space space space space space space space space space space equals 5 straight x to the power of 4 minus 20 straight x cubed plus 45 straight x squared minus 52 straight x plus 11
Answer space in space the space all space the space cases space is space same.
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277. Use Chain Rule to differentiate sin (x2) w.r.t.x.
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278. Use Chain Rule to differentiate w.r.t.x: tan (2 x + 3)
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279. Use Chain Rule to differentiate w.r.t.x: sin (cos x2)
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280. Differentiate w.r.t.x:sin left parenthesis straight x squared plus 5 right parenthesis
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