Class 11 Maths - Quick Formula Notes ✍■
1) Sets:
A ∪ B = union
A ∩ B = intersection
n(A ∪ B) = n(A) + n(B) - n(A ∩ B)
2) Trigonometry:
sin²θ + cos²θ = 1
1 + tan²θ = sec²θ
1 + cot²θ = cosec²θ
sin(A+B) = sinAcosB + cosAsinB
cos(A+B) = cosAcosB - sinAsinB
3) Quadratic Equation:
ax² + bx + c = 0
x = (-b ± √(b² - 4ac)) / 2a
4) Permutation & Combination:
nPr = n! / (n-r)!
nCr = n! / r!(n-r)!
5) Sequence (AP):
nth term = a + (n-1)d
Sum = n/2 [2a + (n-1)d]
6) Straight Line:
y = mx + c
m = (y2 - y1)/(x2 - x1)
7) Circle:
x² + y² = r²
1) Sets:
A ∪ B = union
A ∩ B = intersection
n(A ∪ B) = n(A) + n(B) - n(A ∩ B)
2) Trigonometry:
sin²θ + cos²θ = 1
1 + tan²θ = sec²θ
1 + cot²θ = cosec²θ
sin(A+B) = sinAcosB + cosAsinB
cos(A+B) = cosAcosB - sinAsinB
3) Quadratic Equation:
ax² + bx + c = 0
x = (-b ± √(b² - 4ac)) / 2a
4) Permutation & Combination:
nPr = n! / (n-r)!
nCr = n! / r!(n-r)!
5) Sequence (AP):
nth term = a + (n-1)d
Sum = n/2 [2a + (n-1)d]
6) Straight Line:
y = mx + c
m = (y2 - y1)/(x2 - x1)
7) Circle:
x² + y² = r²
