Question

if theta is an acute angle and 5 cosec theta =7/5;then evaluate sin²theta+cos ²theta-1​

Answer 1

Answer:

sin²Ф+cos²Ф-1​=0

Step-by-step explanation:

sin²Ф+cos²Ф-1​

cosecФ=7/5=H/L

sin Ф =5/7

H=7 and L=5

B=√(49-25)=√24=2√6

So cosФ=B/H=2√6

cosec Ф=7/25=

Now sin²Ф+cos²Ф-1​

=(5/7)²+(2√6/7)²-1

=25/49+24/29-1

=(25+24)/49-1

=1-1=0