Question

Liberty. Paperset - 2020
Std. 10: Mathematics
Vishwabharati English Medium Scho
Time : 3 Hours ]
>
Write answers as per instruction. (1 to 16) (1 mark each)
Following statements are true of false : win
If 3 is one of the zeros of the polynomials p(x) = x2 + 11x + k, then K
The discriminant of equation 25x2 - 5x - 11 = 0 is -63.
For an A.P., the first term can never be zero.
1.
2.
3.
4*.
tan 47: = 1​

Answer 1

Answer:

1.

$p(3) = {3}^{2} + 11 \times 3 + k = 0 \\ 9 + 33 + k = 0 \\ k = - 42$

2. As the discriminant is 1125, the statement is false.

$discriminant \: = {b}^{2} - 4ac \\ a = 25 \: \: \: \: \: \: b = - 5 \: \: \: \: \: c = - 11 \\ discriminant \: = ( { - 5})^{2} - 4 \times 25 \times ( - 11) \\ = 25 + 1100 = 1125$

3. First time of an AP can be 0. So, the statement is false.

4. So, the statement is false.

$\tan(45) = 1$