Q59 of 76 Page 52

If for real values of x, then

Given that,

⇒ x²+1 = x cos θ

⇒ x²- cos θx +1 = 0

We know that, b²-4ac ≥ 0

⇒ (-cos θ)²-4×1×1 ≥ 0

⇒ cos²θ -4 ≥ 0

⇒ cos²θ ≥ 4

⇒ cos θ ≥ ± 2

But -1 ≤ cos θ ≤ 1

So, no value of θ is possible

If then cos 2α is equal to

If then b cos 2θ + a sin 2θ is equal to

Fill in the blanks

The value of is _______.

Fill in the blanks

If k = sin ( pi /18 ) sin ( 5 pi /18 ) sin ( 7 pi /18 ) then the numerical value of k is _________.