Question

Please answer question number 9,10,11,12.

Answer 1

Answer:

9)

7cos²∅ + 3sin²∅ = 3

7cos²∅ + 3(1-cos²∅) = 3

7cos²∅ + 3 - 3cos²∅ = 3

4cos²∅ = 0

cos²∅ = 0

cos∅ = 0

cos90 = 0

hence ∅ = 90°

10)

in 1 to 15 there are 6 prime numbers

probability of the same = 6/15 = 2/5

required probability = 2/5

11)

if roots are real and distinct

then

D >0

b² - 4ac >0