Because integration reverses differentiation, every derivative formula gives a corresponding standard integral. The core standard results (each carries +c):
∫0dx=c and ∫kdx=kx+c (constant k).
Power rule:∫xndx=n+1xn+1+c,(n=−1).
∫x1dx=log∣x∣+c (the n=−1 case).
∫sinxdx=−cosx+c, ∫cosxdx=sinx+c.
∫sec2xdx=tanx+c, ∫cosec2xdx=−cotx+c.
∫secxtanxdx=secx+c, ∫cosecxcotxdx=−cosecx+c.
∫exdx=ex+c, ∫axdx=logaax+c.
∫1−x21dx=sin−1x+c, ∫1+x21dx=tan−1x+c.
Linear-shift rule. When a constant is added/subtracted to x the formula is unchanged; when x is multiplied by a constant, divide by that coefficient: if ∫f(x)dx=g(x)+c, then ∫f(ax+b)dx=a1g(ax+b)+c.
Tip
Rewrite roots and reciprocals as powers (x=x1/2, 1/x3=x−3) before applying the power rule, and never apply the power rule when n=−1 — that case is a logarithm.
Apply the power rule ∫xndx=n+1xn+1+c after rewriting each integrand as a single power of x.
✓Final answer
(i) 12x12+c (ii) −6x61+c (iii) 73x7/3+c (iv) 138x13/8+c
Each part is a pure power of x (after rewriting a reciprocal, a radical, or a power-of-a-power as a single exponent), so the power rule ∫xndx=n+1xn+1+c (n=−1) applies directly in every case.
Step 1. Part (i).x11 is already a single power, n=11.
∫x11dx=12x12+c.
Step 2. Part (ii). Rewrite the reciprocal power as a negative exponent: x71=x−7, so n=−7.
∫x−7dx=−6x−6+c=−6x61+c.
Step 3. Part (iii). Rewrite the cube root as a fractional exponent: 3x4=x4/3, so n=34.
∫x4/3dx=4/3+1x4/3+1+c=7/3x7/3+c=73x7/3+c.
Step 4. Part (iv). A power raised to a power multiplies the exponents: (x5)1/8=x5/8, so n=85.
∫x5/8dx=5/8+1x5/8+1+c=13/8x13/8+c=138x13/8+c.
Step 5. Check by differentiating.dxd(12x12)=x11✓; dxd(−6x61)=6x76=x−7✓; dxd(73x7/3)=x4/3✓; dxd(138x13/8)=x5/8✓ — every antiderivative differentiates back to its integrand.
✓Final answer
(i) 12x12+c (ii) −6x61+c (iii) 73x7/3+c (iv) 138x13/8+c
Power rule, after rewriting reciprocals/radicals/power-of-a-power as a single exponent
Forgetting to convert a reciprocal power like 1/x7 into the negative exponent x−7 before applying the rule
Mis-multiplying the exponents in a power-of-a-power like (x5)1/8