Question

1.IN TRIANGLE ABC,AB=4CM,AC=7CM,ANGLEB=90 DEGREE FIND
SIN C+COS A

Answer 1

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10th

Maths

Introduction to Trigonometry

Trigonometric Ratios

If ABC is right angled at ...

MATHS

If △ABC is right angled at B and BC=7cm,AC−AB=1 cm, then find the value of cosA+sinA.

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ANSWER

ΔABC is right angled at B, so AC is the hypotenuse.

AC−AB=1       ...Given     ....(1)

By Pythagoras theorem,

AC2=AB2+BC2

BC2=AC2−AB2

72=(AC−AB)(AC+AB)

49=1(AC+AB)

So, AC+AB=49     ....(2)

Adding (1) and (2) we get,

⇒2AC=50

⇒AC=25 cm

Sbstitute in eq (2), we get

AB=24 cm.

Now, cosA+sinA=ACAB+ACBC=2524+257=