Concept understanding — Derivatives of Standard Functions
Applying the first-principle limit once to each basic elementary function builds a permanent table; every later problem then differentiates by combining this table with the rules of differentiation (sum/product/quotient/chain/constant-multiple), with no further limit ever required.
Algebraic functions.
dxd(k)=0(k constant),dxd(xn)=nxn−1for any real n(Corollaries 10.1–10.2 extend the integer case to rational, then any real, exponent).
Only sinx→cosx is derived directly from the limit definition (via the sum-to-product identity and limθ→0sinθ/θ=1); every other trig derivative follows from it using the chain rule (cosx=sin(2π+x)) or the quotient rule (tanx=sinx/cosx, etc.) — so the whole trig table rests on a single limit.
The six inverse trigonometric functions (each domain-restricted to its principal branch):
Differentiate the quadratic termwise via the power rule; the result is a straight line, described here since a literal drawing isn't possible in text. …
Step 1. Differentiate f(x)=2x2−5x+3 term by term using the power rule: dxd(2x2)=4x, dxd(−5x)=−5, dxd(3)=0.
Step 2. Combine: f′(x)=4x−5.
Step 3. Describe the graph of f′(x)=4x−5 in place of a literal drawing: it is a straight line with slope 4 and y-intercept −5; it meets the x-axis where 4x−5=0, i.e. x=5/4; since the slope is a positive constant, the line rises everywhere (strict …