Question

Evaluate [ 4sin 30 2sin 60 ] [ 4 5 ]
sin 90 2cos0 5 4

pls solve matrices sum's (idk latex)

Answer 1

Question :

Evaluate $\pmb{\bf{}\left[\begin{array}{ccc}4\;sin30^0&2\;cos60^0\\sin90^0&2cos0^0\end{array}\right] \left[\begin{array}{ccc}4&5\\5&4\end{array}\right]}$.

Solution :

We know :

• sin30° = 1/2
• sin90° = 1
• cos 60° = 1/2
• cos 0° = 1

Substituting we get :

$\rightarrow \pmb{\bf{}\left[\begin{array}{ccc}(4\times\frac{1}{2}) &(2\times\frac{1}{2})\\1&2\times1\end{array}\right] \left[\begin{array}{ccc}4&5\\5&4\end{array}\right]}$

$\rightarrow \pmb{\bf{}\left[\begin{array}{ccc}2&1\\1&2\\\end{array}\right] \left[\begin{array}{ccc}4&5\\5&4\end{array}\right]}$

$\rightarrow \pmb{\bf{\left[\begin{array}{ccc}(2\times4)+(1\times5)\\(1\times4)+(2\times5)\\\end{array}\right] }\left[\begin{array}{ccc}(2\times5)+(1\times4)\\(1\times5)+(2\times4)\\\end{array}\right] }$

$\rightarrow\pmb{\bf{\left[\begin{array}{ccc}13&14\\14&13\end{array}\right] }}$ which is the evaluated answer.

Answer 2

Answer:

see the attachment please