Q4 of 180 Page 4

If angles A

Let the angles A, B and C be ‘a – d’, ‘a’ and ‘a + d’ respectively


[In AP]


By Angle sum property of triangle, we have


∠A + ∠B + ∠C = 180°


⇒ a – d + a + a + d = 180


⇒ 3a = 180


⇒ a = 60°


⇒ ∠B = 60°


OR


Put n = 1


a1= 3(1)2 – 5 = 3 – 5 = -2


Put n = 2


a2= 3(2)2 – 5 = 12- 5 = 7


Put n = 3


a3= 3(3)2 – 5 = 27 – 5 = 22


Common difference, d1= a2 – a1 =7 – (-2) = 9


Common difference, d2 = a3 – a2 = 22 – 9 = 13


Since, d1 ≠ d2


Therefore, it’s not an A.P.


More from this chapter

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2

If x = √p + √q, where p and q are distinct primes then which of the following is a rational number?

A. (√p + √q)2


B. (√p - √q)2


C. (√p + √q)(√p - √q)


D. None of these


OR


Write three irrational numbers between √2 and √3


 3

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6

If the number of zeroes of the polynomial f(x) shown below is t, then find the value of t3 – 3t2 + 9.