#### Thank you for registering.

One of our academic counsellors will contact you within 1 working day.

Click to Chat

1800-5470-145

+91 7353221155

CART 0

• 0
MY CART (5)

Use Coupon: CART20 and get 20% off on all online Study Material

ITEM
DETAILS
MRP
DISCOUNT
FINAL PRICE
Total Price: Rs.

There are no items in this cart.
Continue Shopping

# In triangle abc angle c is obtuse then which is correct a. tana.tanb <1 b. tana.tanb>1 c. none

10 years ago

Hi Rishab,

In case that C is obtuse,

Then C>90.

So A+B msut be less than 90... (because in a triangle A+B+C=180, and C is above 90)

So tan(A+B) must be postivie... (Since A+B is acute < 90)

tan(A+B) = (tanA+tanB)/(1-tanAtanB)

So 1-tanAtanB>0..... (Only then tan(A+B) can be positive)

Hence tanAtanB<1

Option (A) would be the answer.

Best Regards,

10 years ago

In given situation angle c is pbtuse  that means rest two angles a and b are acute (bcoz  sum of trio of angles in a tringle=180)

finding tana = 1/tanb(by figure where c is obtuse angle at middle)

i.e. tana.tanb=1

so the answer is c. none.

plz approve my answer if u like  