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4 problems match “determinants”. Clear

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  1. Area of a triangle from vectors ●○○○○ 10 ptsLet a=(51)\mathbf{a} = \begin{pmatrix} 5 \\ 1 \end{pmatrix} and b=(24)\mathbf{b} = \begin{pmatrix} 2 \\ 4 \end{pmatrix}. Find the area of the triangle with vertices 0\mathbf{0}, a\mathbf{a}, and b\mathbf{b}.
  2. Value of x making a matrix singular ●○○○○ 10 ptsFind the value of xx for which the matrix (1+x73−x8)\begin{pmatrix} 1 + x & 7 \\ 3 - x & 8 \end{pmatrix} is not invertible. Round to two decimal places.
  3. Singular 2x2 matrix parameter ●○○○○ 10 ptsFor which values of λ\lambda does A−1A^{-1} not exist, where A=(λ1−1−λ)A=\begin{pmatrix}\lambda&1\\-1&-\lambda\end{pmatrix}? Give all such values in increasing order.
  4. Cross product of two vectors ●○○○○ 10 ptsFind (2i^+3j^−k^)×(3j^+2k^)(2\hat{i}+3\hat{j}-\hat{k})\times(3\hat{j}+2\hat{k}). Write the result as ai^+bj^+ck^a\hat{i}+b\hat{j}+c\hat{k} and enter the coefficients aa, bb, cc.