NIMCET 2014 — Mathematics PYQ
NIMCET | Mathematics | 2014The value of tan1∘tan2∘tan3∘…tan89∘ is:
Choose the correct answer:
- A.
0
- B.
21
- C.
1
(Correct Answer) - D.
2
1
Explanation
Solution
Concept:
To solve this, we use the following trigonometric properties:
-
tan(90∘−θ)=cotθ
-
tanθ×cotθ=1
-
tan45∘=1
Calculation:
The given expression is:
E=tan1∘tan2∘…tan44∘tan45∘tan46∘…tan88∘tan89∘
We can rewrite the terms from 46∘ to 89∘ using the complementary angle identity:
E=(tan1∘tan2∘…tan44∘)tan45∘[tan(90∘−44∘)…tan(90∘−2∘)tan(90∘−1∘)]
Applying the identity tan(90∘−θ)=cotθ:
E=(tan1∘tan2∘…tan44∘)tan45∘(cot44∘…cot2∘cot1∘)
Now, rearranging the terms to pair tanθ with cotθ:
E=(tan1∘cot1∘)(tan2∘cot2∘)…(tan44∘cot44∘)tan45∘
Since tanθcotθ=1 and tan45∘=1, we get:
E=(1)×(1)×⋯×(1)×1
E=1
Correct Option: 3
Explanation
Solution
Concept:
To solve this, we use the following trigonometric properties:
-
tan(90∘−θ)=cotθ
-
tanθ×cotθ=1
-
tan45∘=1
Calculation:
The given expression is:
E=tan1∘tan2∘…tan44∘tan45∘tan46∘…tan88∘tan89∘
We can rewrite the terms from 46∘ to 89∘ using the complementary angle identity:
E=(tan1∘tan2∘…tan44∘)tan45∘[tan(90∘−44∘)…tan(90∘−2∘)tan(90∘−1∘)]
Applying the identity tan(90∘−θ)=cotθ:
E=(tan1∘tan2∘…tan44∘)tan45∘(cot44∘…cot2∘cot1∘)
Now, rearranging the terms to pair tanθ with cotθ:
E=(tan1∘cot1∘)(tan2∘cot2∘)…(tan44∘cot44∘)tan45∘
Since tanθcotθ=1 and tan45∘=1, we get:
E=(1)×(1)×⋯×(1)×1
E=1
Correct Option: 3

