In DeltaABC, if a = 2, b = 3, c = 4, p...

In `DeltaABC`,
if a = 2, b = 3, c = 4, prove that `cosA=7/8`.

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Knowledge Check

In a DeltaABC , if a = 3, b = 5 and c = 7, find cos c

A

`(1)/(2)`

B

`(1)/(sqrt(2))`

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D

1

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ICSE-PROPERTIES OF TRIANGLE-EXERCISE 7

In DeltaABC, if a = 2, b = 3, c = 4, prove that cosA=7/8.
01:30
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In DeltaABC, if the sides are 7, 4sqrt(3) and sqrt(13) cm, prove tha...
02:31
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In DeltaABC, if a = 9, b = 8, c = 4, prove that 6cosC=4+3cosB.
03:01
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In DeltaABC, The sines of the angles of a triangle are in the ratio ...
07:33
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In DeltaABC, If the two angles of a triangle are 30^(@) and 45^(@) a...
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In DeltaABC, If in a DeltaABC, a = 6, b = 3 and cos(A-B)=4/5, find i...
05:45
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In DeltaABC, In a triangle ABC, angleC=60^(@) and angleA=75^(@). If ...
06:53
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In any DeltaABC, prove that (sinA)/(sin(A+B))=a/c
02:27
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In any DeltaABC, prove that (a-b)/(a+b)=(tan""1/2(A-B))/(tan""1/2(A+...
03:24
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In any DeltaABC, prove that ac""cosB-bc""cosA=a^(2)-b^(2)
02:43
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In any DeltaABC, prove that (sin(A-B))/(sin(A+B))=(a^(2)-b^(2))/c^(2...
02:49
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In any DeltaABC, prove that a(sinB-sinC)+b(sinC-sinA)+c(sinA-sinB)=0
02:35
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In any DeltaABC, prove that acos(A+B+C)-bcos(B+A)-c""cos(A+C)=0
02:13
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In any DeltaABC, prove that a(cosC-cosB)=2(b-c)cos^(2)""1/2A
03:43
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In any DeltaABC, prove that asin""1/2(B-C)=(b-c)cos""1/2A
03:19
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In any DeltaABC, prove that asin(A/2+B)=(b+c)sin""A/2
04:39
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In any DeltaABC, prove that c^(2)=(a-b)^(2)cos^(2)""1/2C+(a+b)^(2)si...
03:42
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In any DeltaABC, prove that asin(B-C)+bsin(C-A)+csin(A-B)=0
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In any DeltaABC, prove that (cos2A)/a^(2)-(cos2B)/b^(2)=1/a^(2)-1/b^...
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In any DeltaABC, prove that (1+cos(A-B)cosC)/(1+cos(A-C)cosB)=(a^(2)...
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