Esercizi sulle derivate
Calcola le seguenti derivate con logaritmi ed esponenziali
1. y = 3x + 2lnx
y' = D(y) = D(3x) + 2D(lnx) = 3xln3 + 2/x
2. y = 2ex - 3lnx - 5x
y' = D(y) = 2D(ex) - 3D(lnx) - 5D(x) = 2ex - 3/x - 5
3. y = ex - 2lnx + 3
y' = D(y) = D(ex) - 2D(lnx) + D(3) = ex - 2/x
4. y = ex-3 = ex/e3
y' = D(y) = 1/e3 D(ex) = ex/e3 = ex-3 = y
5. y = 2cosx - 1/3 lnx + x2
y' = D(y) = 2D(cosx) - 1/3 D(lnx) + D(x2) = -2sinx - 1/(3x) + 2x
6. y = 2ax + 5
y' = D(y) = 2D(ax) + D(5) = 2axlna
7. y = 2lnx - 3y = (1 - 3senx)/x2
y' = D(y) = ((D(1 - 3senx)x2 - (1 - 3senx)D(x2))/(x2)2) = (-3x2cosx - (1 - 3senx)(2x))/x4
= (-3x2cosx - 2x + 6xsenx)/x4 = x(-3xcosx - 2 + 6senx)/x4 = (-3xcosx - 2 + 6senx)/x3
8. y = (x + cosx)/senx
y' = D(y) = (D(x + cosx) · senx - (x + cosx) · D(senx))/sen2x = ((1 - senx)senx - cosx(x + cosx))/sen2x
= (senx - sen2x - xcosx - cos2x)/sen2x = (senx - xcosx - (sen2x + cos2x))/sen2x
= (senx - xcosx - 1)/sen2x
9. y = xx
lny = ln(xx) -> lny = xlnx
D(lny) = D(xlnx)
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1/y y' = xD(lnx) + lnxD(x)
1/y y' = x/x + lnx
1/y y' = 1 + lnx
y' = y(1 + lnx) = xx(1 + lnx)
10. y = (senx)lnx
lny = ln((senx)lnx) -> lny = lnx ln(senx)
D(lny) = D[lnx · ln(senx)]
1/y y' = D(lnx) · ln(senx) + D[ln(senx)] · lnx
1/y y' = ln(senx)/x + lnx · cosx/senx
1/y y' = ln(senx)/x + lnx · cotgx
y' = y[ln(senx)/x + lnx · cotgx] = (senx)lnx[ln(senx)/x + lnx · cotgx]
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