Advertisements
Advertisements
Question
Prove tha `|("bc" - "a"^2, "ca" - "b"^2, "ab" - "c"^2),("ca" - "b"^2, "ab" - "c"^2, "bc" - "a"^2),("ab" - "c"^2, "bc" - "a"^2, "ca" - "b"^2)|` is divisible by a + b + c and find the quotient.
Advertisements
Solution
Δ = `|("bc" - "a"^2, "ca" - "b"^2, "ab" - "c"^2),("ca" - "b"^2, "ab" - "c"^2, "bc" - "a"^2),("ab" - "c"^2, "bc" - "a"^2, "ca" - "b"^2)|`
[Applying C1 → C1 – C2 and C2 → C2 – C3]
Δ = `|("bc" - "a"^2 - "ca" + "b"^2,"ca" - "b"^2 - "ab" + "c"^2, "ab" - "c"^2),("ca" - "b"^2 - "ab" + "c"^2, "ab" - "c"^2 - "bc" + "a"^2, "bc" - "a"^2),("ab" - "c"^2 - "bc" + "a"^2, "bc" - "a"^2 - "ca" + "b"^2, "ca" - "b"^2)|`
= `|(("b" - "a")("a" + "b" + "c"), ("c" - "b")("a" + "b" + "c"), "ab" - "c"^2),(("c" - "b")("a" + "b" + "c"), ("a" - "c")("a" + "b" + "c"), "bc" - "a"^2),(("a" - "c")("a" + "b" + "c"), ("b" - "a")("a" + "b" + "c"), "ca" - "b"^2)|`
[Taking (a + b + c) common from C1 and C2 each]
Δ = `("a" + "b" + "c")^2 |("b" - "a", "c" - "b", "ab" - "c"^2),("c" - "b", "a" - "c", "bc" - "a"^2),("a" - "c", "b" - "a", "ca" - "b"^2)|`
[Applying R1 → R1 + R2 + R3]
Δ = `("a" + "b" + "c")^2 |(0, 0, "ab" + "bc" + "ca" - ("a"^2 + "b"^2 + "c"^2)),("c" - "b", "a" - "c", "bc" - "a"^2),("a" - "c", "b" - "a", "ca" - "b"^2)|`
[Expanding along R1]
Δ = `("a" + "b" + "c")^2 ["ab" + "bc" + "ca" - ("a"^2 + "b"^2 + "c"^2)][("c" - "b")("b" - "a") - ("a" - "c")^2]`
= `("a" + "b" + "c")^2 ("ab" + "bc" + "ca" - "a"^2 - "b"^2 - "c"^2) xx ("bc" - "ac" - "b"^2 + "ab" - "a"^2 - "c"^2 + 2"ac")`
= (a + b + c)[(a + b + c)(a2 + b2 + c2 – ab – bc – ca)2]
Hence, given determinant is divisible by (a + b + c) and quotient is (a + b + c)(a2 + b2 + c2 – ab – bc – ca)2
APPEARS IN
RELATED QUESTIONS
If A = `[(1,1,-2),(2,1,-3),(5,4,-9)]`, find |A|.
Find the value of x, if `|(2,3),(4,5)|=|(x,3),(2x,5)|`.
Without expanding at any stage, find the value of:
`|(a,b,c),(a+2x,b+2y,c+2z),(x,y,z)|`
A matrix A of order 3 × 3 has determinant 5. What is the value of |3A|?
On expanding by first row, the value of the determinant of 3 × 3 square matrix
\[A = \left[ a_{ij} \right]\text{ is }a_{11} C_{11} + a_{12} C_{12} + a_{13} C_{13}\] , where [Cij] is the cofactor of aij in A. Write the expression for its value on expanding by second column.
Let A = [aij] be a square matrix of order 3 × 3 and Cij denote cofactor of aij in A. If |A| = 5, write the value of a31 C31 + a32 C32 a33 C33.
Solve the following system of linear equations using matrix method:
3x + y + z = 1
2x + 2z = 0
5x + y + 2z = 2
Using matrices, solve the following system of linear equations :
x + 2y − 3z = −4
2x + 3y + 2z = 2
3x − 3y − 4z = 11
Without expanding, show that Δ = `|("cosec"^2theta, cot^2theta, 1),(cot^2theta, "cosec"^2theta, -1),(42, 40, 2)|` = 0
If Δ = `|(0, "b" - "a", "c" - "a"),("a" - "b", 0, "c" - "b"),("a" - "c", "b" - "c", 0)|`, then show that ∆ is equal to zero.
If x, y ∈ R, then the determinant ∆ = `|(cosx, -sinx, 1),(sinx, cosx, 1),(cos(x + y), -sin(x + y), 0)|` lies in the interval.
The determinant ∆ = `|(sqrt(23) + sqrt(3), sqrt(5), sqrt(5)),(sqrt(15) + sqrt(46), 5, sqrt(10)),(3 + sqrt(115), sqrt(15), 5)|` is equal to ______.
The value of the determinant ∆ = `|(sin^2 23^circ, sin^2 67^circ, cos180^circ),(-sin^2 67^circ, -sin^2 23^circ, cos^2 180^circ),(cos180^circ, sin^2 23^circ, sin^2 67^circ)|` = ______.
If a1, a2, a3, ..., ar are in G.P., then prove that the determinant `|("a"_("r" + 1), "a"_("r" + 5), "a"_("r" + 9)),("a"_("r" + 7), "a"_("r" + 11), "a"_("r" + 15)),("a"_("r" + 11), "a"_("r" + 17), "a"_("r" + 21))|` is independent of r.
If a + b + c ≠ 0 and `|("a", "b","c"),("b", "c", "a"),("c", "a", "b")|` 0, then prove that a = b = c.
If x + y + z = 0, prove that `|(x"a", y"b", z"c"),(y"c", z"a", x"b"),(z"b", x"c", y"a")| = xyz|("a", "b", "c"),("c", "a", "b"),("b", "c", "a")|`
If f(x) = `|(0, x - "a", x - "b"),(x + "b", 0, x - "c"),(x + "b", x + "c", 0)|`, then ______.
If A = `[(2, lambda, -3),(0, 2, 5),(1, 1, 3)]`, then A–1 exists if ______.
If x, y, z are all different from zero and `|(1 + x, 1, 1),(1, 1 + y, 1),(1, 1, 1 + z)|` = 0, then value of x–1 + y–1 + z–1 is ______.
`|(0, xyz, x - z),(y - x, 0, y z),(z - x, z - y, 0)|` = ______.
If f(x) = `|((1 + x)^17, (1 + x)^19, (1 + x)^23),((1 + x)^23, (1 + x)^29, (1 + x)^34),((1 +x)^41, (1 +x)^43, (1 + x)^47)|` = A + Bx + Cx2 + ..., then A = ______.
If A and B are matrices of order 3 and |A| = 5, |B| = 3, then |3AB| = 27 × 5 × 3 = 405.
The maximum value of `|(1, 1, 1),(1, (1 + sintheta), 1),(1, 1, 1 + costheta)|` is `1/2`
If A, B, and C be the three square matrices such that A = B + C, then Det A is equal to
If A = `[(1,0,0),(2,"cos x","sin x"),(3,"sin x", "-cos x")],` then det. A is equal to ____________.
If `"abc" ne 0 "and" abs ((1 + "a", 1, 1),(1, 1 + "b", 1),(1,1,1 + "c")) = 0, "then" 1/"a" + 1/"b" + 1/"c" =` ____________.
Let A be a square matrix of order 2 x 2, then `abs("KA")` is equal to ____________.
For positive numbers x, y, z the numerical value of the determinant `|(1, log_x y, log_x z),(log_y x, 3, log_y z),(log_z x, log_z y, 5)|` is
For positive numbers x, y, z, the numerical value of the determinant `|(1, log_x y, log_x z),(log_y x, 1, log_y z),(log_z x, log_z y, 1)|` is
The value of determinant `|(sin^2 13°, sin^2 77°, tan135°),(sin^2 77°, tan135°, sin^2 13°),(tan135°, sin^2 13°, sin^2 77°)|` is
Value of `|(2, 4),(-1, 2)|` is
