Qus : 4 Phrases PYQ 2019 3 If a , a , a 2 , . , a 2 n − 1 , b are in AP, a , b 1 , b 2 , . . . b 2 n − 1 , b are in GP and a , c 1 , c 2 , . . . c 2 n − 1 , b are in HP, where a, b are positive, then the
equation a n x 2 − b n + c n has its roots
1 Real and equal 2 Real and unequal 3 imaginary 4 One real and one imaginary Go to Discussion
Phrases Previous Year PYQ
Phrases NIMCET 2019 PYQ
Qus : 6 Phrases PYQ 2024 3 The number of solutions of 5 1 + | sin x | + | sin x | 2 + … = 25 for x ∈ ( − π , π ) is
1 2 2 0
3 4 4 ∞ Go to Discussion
Phrases Previous Year PYQ
Phrases NIMCET 2024 PYQ
Solution
Step 1: Recognize the series
The exponent is an infinite geometric series:
1 + | sin x | + | sin x | 2 + | sin x | 3 + ⋯
This is a geometric series with first term a = 1 , common ratio r = | sin x | ∈ [ 0 , 1 ] , so:
Sum = 1 1 − | sin x |
Step 2: Rewrite the equation
5 1 1 − | sin x | = 25 = 5 2
Equating exponents:
1 1 − | sin x | = 2 ⇒ 1 − | sin x | = 1 2 ⇒ | sin x | = 1 2
Step 3: Solve for x ∈ ( − π , π )
We want all x ∈ ( − π , π ) such that | sin x | = 1 2
So sin x = ± 1 2 . Within ( − π , π ) , the values of x satisfying this are:
✅ Final Answer: 4 solutions
Qus : 9 Phrases PYQ 2024 1 If one AM (Arithmetic mean) 'a' and two GM's (Geometric means) p and q be inserted between any two positive numbers, the value of p^3+q^3 is
1 2apq 2 pq/a 3 2pq/a 4 p+q+a Go to Discussion
Phrases Previous Year PYQ
Phrases NIMCET 2024 PYQ
Solution
Problem:
If one Arithmetic Mean (AM) a and two Geometric Means p and q are inserted between any two positive numbers, find the value of:
p 3 + q 3
Given:
Let two positive numbers be A and B .
One AM: a = A + B 2
Two GMs inserted: so the four terms in G.P. are:
A , p = 3 √ A 2 B , q = 3 √ A B 2 , B
Now calculate:
p q = 3 √ A 2 B ⋅ 3 √ A B 2 = 3 √ A 3 B 3 = A B
p 3 = A 2 B , q 3 = A B 2
p 3 + q 3 = A 2 B + A B 2 = A B ( A + B )
Also,
2 a p q = 2 ⋅ A + B 2 ⋅ A B = A B ( A + B )
✅ Therefore,
p 3 + q 3 = 2 a p q
Qus : 14 Phrases PYQ 2017 1 Three positive number whose sum is 21 are in arithmetic progression. If 2, 2, 14 are added to them respectively then resulting numbers are in geometric progression. Then which of the following is not among the three numbers?
1 25 2 13 3 1 4 7 Go to Discussion
Phrases Previous Year PYQ
Phrases NIMCET 2017 PYQ
Solution Let the three terms in A.P. be a – d, a, a + d.
given that a – d + a + a + d = 21
a = 7
then the three term in A.P. are 7 – d, 7, 7 + d
According to given condition 9 – d, 9, 21 + d are in G.P.
(9)2 = (9 – d) (21 + d)
81 = 189 + 9d – 21d – d2
81 = 189 – 12d – d2
d2 + 12d – 108 = 0
d(d + 18) – 6 (d + 18) = 0
(d – 6) (d + 18) = 0
We get, d = 6, –18
Putting d = 6 in the term 7 – d, 7, 7 + d we get 1, 7, 13.
Qus : 21 Phrases PYQ 2023 3 The sum of infinite terms of decreasing GP is equal to the greatest value of the function f(x) = x^3
+ 3x – 9 in the
interval [–2, 3] and difference between the first two terms is f '(0). Then the common ratio of the GP is
1 \frac{-2}{3} 2 \frac{4}{3} 3 \frac{+2}{3} 4 \frac{-4}{3} Go to Discussion
Phrases Previous Year PYQ
Phrases NIMCET 2023 PYQ
Solution
? GP and Function Relation
Given: f(x) = x^3 + 3x - 9
The sum of infinite GP = max value of f(x) on [−2, 3]
The difference between first two terms = f'(0)
Step 1: f(x) is increasing ⇒ Max at x = 3
f(3) = 27 \Rightarrow \frac{a}{1 - r} = 27
Step 2: f'(x) = 3x^2 + 3 \Rightarrow f'(0) = 3
⇒ a(1 - r) = 3
Step 3: Solve:
a = 27(1 - r)
\Rightarrow 27(1 - r)^2 = 3 \Rightarrow (1 - r)^2 = \frac{1}{9} \Rightarrow r = \frac{2}{3}
✅ Final Answer:
r = \frac{2}{3}
[{"qus_id":"3776","year":"2018"},{"qus_id":"3752","year":"2018"},{"qus_id":"3751","year":"2018"},{"qus_id":"3900","year":"2019"},{"qus_id":"3939","year":"2019"},{"qus_id":"3932","year":"2019"},{"qus_id":"3931","year":"2019"},{"qus_id":"4267","year":"2017"},{"qus_id":"4278","year":"2017"},{"qus_id":"9447","year":"2020"},{"qus_id":"10684","year":"2021"},{"qus_id":"10689","year":"2021"},{"qus_id":"11125","year":"2022"},{"qus_id":"11145","year":"2022"},{"qus_id":"11508","year":"2023"},{"qus_id":"11517","year":"2023"},{"qus_id":"11630","year":"2024"},{"qus_id":"11631","year":"2024"},{"qus_id":"11658","year":"2024"},{"qus_id":"4517","year":"2016"},{"qus_id":"10202","year":"2015"},{"qus_id":"10203","year":"2015"}]