Question

Help me please friends

Answer 1

Answer:

10 answer is c

9 answer is c

8 answer is -13

Answer 2

Answer:

Step-by-step explanation:

8.

For a quadratic eqn ax^2 + bx + c

Product of root is given by c/a

Here, if one root is @ then other root is 1/@

Product of root = @ * 1/@ = 1

For 5x^2 + 13x - k =0

Product of root = -k/5

-k/5 = 1

k = -5

9.

cot( 90-@ ) = tan @

cot 61 = cot( 90 - 29 ) = tan 29

Since,sec^2 @ - tan^2 @ = 1

17sec^2(29) - 17cot^2(61)

=17sec^2(29) - 17tan^2(29)

=17 [ sec^2(29) - tan^2(29) ]

=17

10.

cos 90 = 0

so,

cos 1 * cos 2 * cos 3 * ...........* cos 180

=cos 1 * cos 2 * .............* cos 90 *.......*cos 180

=cos 1 * cos 2 * ........* 0 * ....* cos 180

=0

Hope it helps :-)