All Important Formula — Class 12 Maths Notes
All Important Formula · Class 12 Maths · 6 topics.
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Topics covered in All Important Formula
1.Algebraic Formulas:
Algebraic Formulas:
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(a+b)2=a2+2ab+b2
- Expansion of a binomial square (sum of squares).
- Expansion of a binomial square (sum of squares).
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(a−b)2=a2−2ab+b2(a - b)^2 = a^2 - 2ab + b^2
- Expansion of a binomial square (difference of squares).
- Expansion of a binomial square (difference of squares).
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(a+b)(a−b)=a2−b2(a + b)(a - b) = a^2 - b^2
- Difference of squares formula.
- Difference of squares formula.
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a3+b3=(a+b)(a2−ab+b2)a^3 + b^3 = (a + b)(a^2 - ab + b^2)
- Sum of cubes.
- Sum of cubes.
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a3−b3=(a−b)(a2+ab+b2)a^3 - b^3 = (a - b)(a^2 + ab + b^2)
- Difference of cubes.
- Difference of cubes.
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(a−b2)2=a2−2ab+b24\left(\frac{a - b}{2}\right)^2 = \frac{a^2 - 2ab + b^2}{4}
- Square of a fraction involving binomial subtraction.
- Square of a fraction involving binomial subtraction.
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a3−b3=(a−b)(a2+ab+b2)+3ab(a−b)a^3 - b^3 = (a - b)(a^2 + ab + b^2) + 3ab(a - b)
- Another variation for the difference of cubes expansion.
- Another variation for the difference of cubes expansion.
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(a−b)4=a4−4a3b+6a2b2−4ab3+b4(a - b)^4 = a^4 - 4a^3b + 6a^2b^2 - 4ab^3 + b^4
- Fourth power binomial expansion (difference).
- Fourth power binomial expansion (difference).
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a3+b3=(a+b)3−3ab(a+b)a^3 + b^3 = (a + b)^3 - 3ab(a + b)
- Sum of cubes in terms of a binomial cube.
- Sum of cubes in terms of a binomial cube.
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(a+b)3=a3+3a2b+3ab2+b3(a + b)^3 = a^3 + 3a^2b + 3ab^2 + b^3
- Cube of a binomial (sum).
- Cube of a binomial (sum).
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(a−b)3=a3−3a2b+3ab2−b3(a - b)^3 = a^3 - 3a^2b + 3ab^2 - b^3
- Cube of a binomial (difference).
- Cube of a binomial (difference).
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(a−b)3=a3−3a2b+3ab2−b3(a - b)^3 = a^3 - 3a^2b + 3ab^2 - b^3
- Repeated cube of a binomial (difference).
Explanation and Example of Key Formula
Formula: (a+b)2=a2+2ab+b2(a + b)^2 = a^2 + 2ab + b^2
Components:- aa and bb are variables or numbers.
- The square of the sum of aa and bb expands to a2+2ab+b2a^2 + 2ab + b^2.
Example:
Let's expand (3+2)2(3 + 2)^2:
- Given: a=3a = 3, b=2
b = 2 - Plug into the formula: (3+2)2=32+2×3×2+22(3 + 2)^2 = 3^2 + 2 \times 3 \times 2 + 2^2
- Simplify: =9+12+4=25
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2.Factors Formula (Logarithmic Formulas)
1. ax=N ⟹ x=logaNa^x = N \implies x = \log_a N
Explanation: If aa raised to the power xx equals NN, then xx is the logarithm of NN with base aa.
Example:
If 23=82^3 = 8, then log28=3\log_2 8 = 3.
2. logaa=1\log_a a = 1
Explanation: The logarithm of a number to its own base is always 1.
Example:
log55=1\log_5 5 = 1.
3. log1010=1\log_{10} 10 = 1
Explanation: The logarithm of 10 to the base 10 is always 1.
Example:
log1010=1\log_{10} 10 = 1.
4. loga(m×n)=logam+logan\log_a (m \times n) = \log_a m + \log_a n
Explanation: The logarithm of the product of two numbers is the sum of their logarithms to the same base.
Example:
Find log2(8×4)\log_2 (8 \times 4): log2(8×4)=log28+log24\log_2 (8 \times 4) = \log_2 8 + \log_2 4 Since log28=3\log_2 8 = 3 and log24=2\log_2 4 = 2: log2(8×4)=3+2=5\log_2 (8 \times 4) = 3 + 2 = 5
5. loga(mn)=logam−logan\log_a \left(\frac{m}{n}\right) = \log_a m - \log_a n
Explanation: The logarithm of the division of two numbers is the difference of their logarithms.
Example:
Find log2(84)\log_2 \left(\frac{8}{4}\right): log2(84)=log28−log24\log_2 \left(\frac{8}{4}\right) = \log_2 8 - \log_2 4 Since log28=3\log_2 8 = 3 and log24=2\log_2 4 = 2: log2(84)=3−2=1\log_2 \left(\frac{8}{4}\right) = 3 - 2 = 1
6. logamn=nlogam\log_a m^n = n \log_a m
Explanation: The logarithm of a power is the exponent times the logarithm of the base number.
Example:
Find log282\log_2 8^2: log282=2log28\log_2 8^2 = 2 \log_2 8 Since log28=3\log_2 8 = 3: log282=2×3=6\log_2 8^2 = 2 \times 3 = 6
7. logax2=2loga∣x∣\log_a x^2 = 2 \log_a |x|
Explanation: The logarithm of x2x^2 is twice the logarithm of the absolute value of xx.
Example:
Find log2(−4)2\log_2 (-4)^2: log2(−4)2=2log2∣4∣\log_2 (-4)^2 = 2 \log_2 |4| Since log24=2\log_2 4 = 2: log2(−4)2=2×2=4\log_2 (-4)^2 = 2 \times 2 = 4
8. logba×logab=1\log_b a \times \log_a b = 1
Explanation: The product of logba\log_b a and logab\log_a b is always equal to 1.
Example:
If log39=2\log_3 9 = 2, then log93=12\log_9 3 = \frac{1}{2}, and their product: log39×log93=2×12=1\log_3 9 \times \log_9 3 = 2 \times \frac{1}{2} = 1
9. logab=1logba\log_a b = \frac{1}{\log_b a}
Explanation: The logarithm of bb with base aa is the reciprocal of the logarithm of aa with base bb.
Example:
If log28=3\log_2 8 = 3, then log82=13\log_8 2 = \frac{1}{3}.
10. logbx=logaxlogab\log_b x = \frac{\log_a x}{\log_a b}
Explanation: This is the change of base formula, which allows you to convert logarithms from one base to another.
Example:
Find log28\log_2 8 using base 10: log28=log108log102\log_2 8 = \frac{\log_{10} 8}{\log_{10} 2} Approximate values: log108≈0.903,log102≈0.301\log_{10} 8 \approx 0.903, \quad \log_{10} 2 \approx 0.301 So, log28≈0.9030.301=3\log_2 8 \approx \frac{0.903}{0.301} = 3
11. logba=1logab\log_b a = \frac{1}{\log_a b}
- Explanation: This is a repetition of Formula 9, stating the reciprocal relationship of logs.
Example:
If log525=2\log_5 25 = 2, then log255=12\log_{25} 5 = \frac{1}{2}.
3.Trigonometric Ratios and Formulas
📏 Trigonometric Ratios and Formulas
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Trigonometric Ratios:
- tanθ=sinθcosθ
\tan \theta = \frac{\sin \theta}{\cos \theta} - cotθ=cosθsinθ
\cot \theta = \frac{\cos \theta}{\sin \theta} - secθ=1cosθ
\sec \theta = \frac{1}{\cos \theta} - cscθ=1sinθ
\csc \theta = \frac{1}{\sin \theta}
- tanθ=sinθcosθ
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Pythagorean Identities:
- sin2θ+cos2θ=1\sin^2 \theta + \cos^2 \theta = 1
- sec2θ−tan2θ=1\sec^2 \theta - \tan^2 \theta = 1
- csc2θ−cot2θ=1
\csc^2 \theta - \cot^2 \theta = 1
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Co-function Identities:
- sinθ=cos(90∘−θ)\sin \theta = \cos (90^\circ - \theta)
- cosθ=sin(90∘−θ)\cos \theta = \sin (90^\circ - \theta)
- tanθ=cot(90∘−θ)\tan \theta = \cot (90^\circ - \theta)
- cotθ=tan(90∘−θ)\cot \theta = \tan (90^\circ - \theta)
- secθ=csc(90∘−θ)\sec \theta = \csc (90^\circ - \theta)
- cscθ=sec(90∘−θ)
\csc \theta = \sec (90^\circ - \theta)
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Additional Identities:
- tanθ×cotθ=1\tan \theta \times \cot \theta = 1
📊 Trigonometric Table for Common Angles
These formulas and table help solve problems related to trigonometry, geometry, and real-world applications like physics, architecture, and engineering.-
4.Differentiation Formulas
Basic Differentiation Formulas
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Power Rule
ddx(xn)=nxn−1\frac{d}{dx}(x^n) = n x^{n-1} -
Exponential Function
ddx(ex)=ex\frac{d}{dx}(e^x) = e^x -
Logarithmic Differentiation
ddx(logax)=1xloga
\frac{d}{dx}(\log_a x) = \frac{1}{x \log a} -
Natural Logarithm
ddx(logex)=1x
\frac{d}{dx}(\log_e x) = \frac{1}{x} -
Exponential with Base aa
ddx(ax)=axloga\frac{d}{dx}(a^x) = a^x \log a
Trigonometric Functions
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Derivative of sinx\sin x
ddx(sinx)=cosx
\frac{d}{dx}(\sin x) = \cos x -
Derivative of cosx\cos x
ddx(cosx)=−sinx
\frac{d}{dx}(\cos x) = -\sin x -
Derivative of tanx\tan x
ddx(tanx)=sec2x
\frac{d}{dx}(\tan x) = \sec^2 x -
Derivative of cotx\cot x
ddx(cotx)=−csc2x
\frac{d}{dx}(\cot x) = -\csc^2 x -
Derivative of secx\sec x
ddx(secx)=secxtanx
\frac{d}{dx}(\sec x) = \sec x \tan x -
Derivative of cscx\csc x
ddx(cscx)=−cscxcotx\frac{d}{dx}(\csc x) = -\csc x \cot x
Inverse Trigonometric Functions
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Derivative of sin−1x\sin^{-1} x
ddx(sin−1x)=11−x2,for −1<x<1
\frac{d}{dx}(\sin^{-1} x) = \frac{1}{\sqrt{1 - x^2}}, \quad \text{for } -1 < x < 1 -
Derivative of cos−1x\cos^{-1} x
ddx(cos−1x)=−11−x2,for −1<x<1
\frac{d}{dx}(\cos^{-1} x) = -\frac{1}{\sqrt{1 - x^2}}, \quad \text{for } -1 < x < 1 -
Derivative of tan−1x\tan^{-1} x
ddx(tan−1x)=11+x2\frac{d}{dx}(\tan^{-1} x) = \frac{1}{1 + x^2} -
Derivative of cot−1x\cot^{-1} x
ddx(cot−1x)=−11+x2\frac{d}{dx}(\cot^{-1} x) = -\frac{1}{1 + x^2} -
Derivative of sec−1x\sec^{-1} x
ddx(sec−1x)=1∣x∣x2−1,∣x∣>1
\frac{d}{dx}(\sec^{-1} x) = \frac{1}{|x| \sqrt{x^2 - 1}}, \quad |x| > 1 -
Derivative of csc−1x\csc^{-1} x
ddx(csc−1x)=−1∣x∣x2−1,∣x∣>1\frac{d}{dx}(\csc^{-1} x) = -\frac{1}{|x| \sqrt{x^2 - 1}}, \quad |x| > 1
Hyperbolic Trigonometric Functions
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Derivative of sinhx\sinh x
ddx(sinhx)=coshx
\frac{d}{dx}(\sinh x) = \cosh x -
Derivative of coshx\cosh x
ddx(coshx)=sinhx
\frac{d}{dx}(\cosh x) = \sinh x -
Derivative of tanhx\tanh x
ddx(tanhx)=sech2x
\frac{d}{dx}(\tanh x) = \operatorname{sech}^2 x -
Derivative of cothx\coth x
ddx(cothx)=−csch2x
\frac{d}{dx}(\coth x) = -\operatorname{csch}^2 x -
Derivative of sechx\operatorname{sech} x
ddx(sechx)=−sechxtanhx
\frac{d}{dx}(\operatorname{sech} x) = -\operatorname{sech} x \tanh x -
Derivative of cschx\operatorname{csch} x
ddx(cschx)=−cschxcothx
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5.Integration Formulas
1. Basic Formulas
- ∫1 dx=x+C
\int 1 \, dx = x + C - ∫xn dx=xn+1n+1+C\int x^n \, dx = \frac{x^{n+1}}{n+1} + C (for n≠−1n \neq -1)
- ∫ex dx=ex+C
\int e^x \, dx = e^x + C - ∫ax dx=axlna+C\int a^x \, dx = \frac{a^x}{\ln a} + C (for a>0,a≠1a > 0, a \neq 1)
- ∫1x dx=ln∣x∣+C\int \frac{1}{x} \, dx = \ln |x| + C
2. Trigonometric Formulas
- ∫sinx dx=−cosx+C
\int \sin x \, dx = -\cos x + C - ∫cosx dx=sinx+C
\int \cos x \, dx = \sin x + C - ∫sec2x dx=tanx+C
\int \sec^2 x \, dx = \tan x + C - ∫csc2x dx=−cotx+C
\int \csc^2 x \, dx = -\cot x + C - ∫secxtanx dx=secx+C
\int \sec x \tan x \, dx = \sec x + C - ∫cscxcotx dx=−cscx+C\int \csc x \cot x \, dx = -\csc x + C
3. Inverse Trigonometric Formulas
- ∫11−x2 dx=sin−1x+C
\int \frac{1}{\sqrt{1-x^2}} \, dx = \sin^{-1}x + C - ∫−11−x2 dx=cos−1x+C
\int \frac{-1}{\sqrt{1-x^2}} \, dx = \cos^{-1}x + C - ∫11+x2 dx=tan−1x+C
\int \frac{1}{1+x^2} \, dx = \tan^{-1}x + C - ∫−11+x2 dx=cot−1x+C
\int \frac{-1}{1+x^2} \, dx = \cot^{-1}x + C - ∫1xx2−1 dx=sec−1∣x∣+C
\int \frac{1}{x\sqrt{x^2-1}} \, dx = \sec^{-1}|x| + C - ∫−1xx2−1 dx=csc−1∣x∣+C\int \frac{-1}{x\sqrt{x^2-1}} \, dx = \csc^{-1}|x| + C
4. Exponential and Logarithmic Functions
- ∫ex dx=ex+C
\int e^x \, dx = e^x + C - ∫lnx dx=xlnx−x+C
\int \ln x \, dx = x\ln x - x + C - ∫ax dx=axlna+C\int a^x \, dx = \frac{a^x}{\ln a} + C
5. Special Forms
- ∫1a2+x2 dx=1atan−1xa+C
\int \frac{1}{a^2 + x^2} \, dx = \frac{1}{a} \tan^{-1} \frac{x}{a} + C - ∫1a2−x2 dx=sin−1xa+C
\int \frac{1}{\sqrt{a^2 - x^2}} \, dx = \sin^{-1} \frac{x}{a} + C - ∫1xx2−a2 dx=1asec−1∣x∣a+C\int \frac{1}{x\sqrt{x^2 - a^2}} \, dx = \frac{1}{a} \sec^{-1} \frac{|x|}{a} + C
6. Integration by Substitution
If u=f(x)u = f(x), then:
∫f′(x)g(f(x)) dx=∫g(u) du\int f'(x)g(f(x)) \, dx = \int g(u) \, du
7. Integration by Parts
∫uv dx=u∫v dx−∫(dudx∫v dx)dx\int u v \, dx = u \int v \, dx - \int \left( \frac{du}{dx} \int v \, dx \right) dx
Where uu and vv are functions of xx.
8. Definite Integral Properties
- ∫abf(x) dx=F(b)−F(a)\int_a^b f(x) \, dx = F(b) - F(a), where F(x)F(x) is the antiderivative of f(x)f(x).
- ∫aaf(x) dx=0
\int_a^a f(x) \, dx = 0 - ∫abf(x) dx=−∫baf(x) dx
- ∫1 dx=x+C
6.Exponent Laws
Exponent Laws
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a0=1a^0 = 1
- Explanation: Any non-zero number raised to the power of 00 is always 11.
- Explanation: Any non-zero number raised to the power of 00 is always 11.
-
ap⋅aq=ap+qa^p \cdot a^q = a^{p+q}
- Explanation: When multiplying two numbers with the same base, add the exponents.
- Explanation: When multiplying two numbers with the same base, add the exponents.
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(ap)q=ap⋅q(a^p)^q = a^{p \cdot q}
- Explanation: When raising a power to another power, multiply the exponents.
- Explanation: When raising a power to another power, multiply the exponents.
-
apaq=ap−q\frac{a^p}{a^q} = a^{p-q}
- Explanation: When dividing two numbers with the same base, subtract the exponents.
- Explanation: When dividing two numbers with the same base, subtract the exponents.
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a−n=1ana^{-n} = \frac{1}{a^n}
- Explanation: A negative exponent means the reciprocal of the number raised to the positive exponent.
- Explanation: A negative exponent means the reciprocal of the number raised to the positive exponent.
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a=a1/2\sqrt{a} = a^{1/2}
- Explanation: The square root of a number can be expressed as the number raised to the power 1/21/2.
- Explanation: The square root of a number can be expressed as the number raised to the power 1/21/2.
-
a3=a1/3\sqrt[3]{a} = a^{1/3}
- Explanation: The cube root of a number can be expressed as the number raised to the power 1/31/3.
- Explanation: The cube root of a number can be expressed as the number raised to the power 1/31/3.
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an=a1/n\sqrt[n]{a} = a^{1/n}
- Explanation: The nn-th root of a number can be expressed as the number raised to the power 1/n1/n.
- Explanation: The nn-th root of a number can be expressed as the number raised to the power 1/n1/n.
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a1=aa^1 = a
- Explanation: Any number raised to the power 11 is the number itself.
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