85393 The approximate value of (1.002)300 using differentiation is
(B) : Given,x+Δx=1.002x=1Δx=0.002Let,f(x)=x300f′(x)=300x299We know that,f(x+Δx)=f(x)+Δx.f′(x)f(1.002)=f(1)+0.002×300(1)299f(1.002)=1+0.002×300=1+0.6f(1.002)=1.6
85394 Using differentiation, the approximate value of sin46∘,Given that 10=0.0175∘, is
(B) : Givenf(x)=sinxf′(x)=cosx46∘=45∘+1∘1∘=0.0175(x+Δx)=46∘x=45∘Δx=1∘=0.0175We know that,f(x+Δx)=f′(x)Δx+f(x)=cos45∘×(0.0175)+sin45∘=12(0.0175)+12=12[0.0175+1]=1.01752So, the approximate value of sin46∘=1.01752
85395 The slope of normal to the curve x=t andy=t−1t at t=4 is (a) 174 (b) −174 (c) 417 (d) −417
(D) : Given,x=t,y=t−1t at t=4Now, dxdt=12tSimilarly dydt=1+12t−3/2∴dydx=dydtdxdt=(1+12t−3/2)12t=2t(1+12t−3/2)=2t(1+12t3/2)dydx=2t3/2+1tAt, on putting t=4dydx=2(4)3/2+14=174∴ Slope of normal at (t=4)=−1dydx=−417
85396 The equation of normal to the curve y=logex at the point P(1,0) is
(A) : Given,Curve, y=logexOn differentiating w.r.t x,dydx=1x∴ Slope of normal at P=(1,0)=−1(dydx)(1,0)=−11=−1∴ Equation of normal at P=(1,0)y−0=(−1)(x−1)y=−x+1x+y=1