Distance formula |
Fig. 21.2 |
d = (x2 − x1)2 + (y2 − y1)2−−−−−−−−−−−−−−−−−−√ (21.1) |
Slope |
Fig. 21.4 |
m = y2 − y1x2 − x1 (21.2) |
|
Fig. 21.7 |
m = tan α(0 ° ≤ α < 180 ° ) (21.3) |
|
Fig. 21.9 |
m1 = m2(for | | lines) (21.4) |
|
Fig. 21.10 |
m2 = − 1m1or m1m2 = − 1(for ⊥ lines) (21.5) |
Straight line |
Fig. 21.15 |
y − y1 = m(x − x1) (21.6) |
|
Fig. 21.18 |
|
|
Fig. 21.19 |
|
|
Fig. 21.22 |
y = mx + b (21.9) |
|
|
Ax + By + C = 0 (21.10) |
Circle |
Fig. 21.30 |
(x − h)2 + (y − k)2 = r2 (21.11) |
|
Fig. 21.33 |
x2 + y2 = r2 (21.12) |
|
|
x2 + y2 + Dx + Ey + F = 0 (21.14) |
Parabola |
Fig. 21.43 |
|
|
Fig. 21.46 |
|
Ellipse |
Fig. 21.58 |
x2a2 + y2b2 = 1 (21.17) |
|
Fig. 21.58 |
a2 = b2 + c2 (21.18) |
|
Fig. 21.59 |
y2a2 + x2b2 = 1 (21.19) |
Hyperbola |
Fig. 21.71 |
x2a2 − y2b2 = 1 (21.20) |
|
Fig. 21.71 |
c2 = a2 + b2 (21.21) |
|
Fig. 21.70 |
y = ± bxa(asymptotes) (21.23) |
|
Fig. 21.72 |
y2a2 − x2b2 = 1 (21.24) |
|
Fig. 21.78 |
|
Translation of axes |
Fig. 21.83 |
x = x ′ + hand y = y ′ + k (21.26) |
|
|
x ′ = x − hand y ′ = y − k (21.27) |
Parabola, vertex (h, k) |
|
(y − k)2 = 4p(x − h)(axis parallel to x-axis) (21.28) |
|
|
(x − h)2 = 4p(y − k)(axis parallel to y- axis) (21.29) |
Ellipse, center (h, k) |
|
(x − h)2a2 + (y − k)2b2 = 1(major axis parallel to x-axis) (21.30) |
|
|
(y − k)2a2 + (x − h)2b2 = 1(major axis parallel to y-axis) (21.31) |
Hyperbola, center (h, k) |
|
(x − h)2a2 − (y − k)2b2 = 1(transverse axis parallel to x-axis) (21.32) |
|
|
(y − k)2a2 − (x − h)2b2 = 1(transverse axis parallel to y-axis) (21.33) |
Second-degree equation |
|
Ax2 + Bxy + Cy2 + Dx + Ey + F = 0 (21.34) |
Rotation of axes |
Fig. 21.97 |
xy = = x ′ cos θ − y ′ sin θx ′ sin θ + y ′ cos θ |
Angle of rotation |
|
tan 2θ = BA − C(A ≠ C) (21.39) |
|
|
θ = 45 ° (A = C) (21.40) |
Polar coordinates |
Fig. 21.106 |
x = r cos θy = r sin θ (21.41) |
|
|
tan θ = yxr = x2 + y2−−−−−−√ (21.42) |