Question

prove cos theta minus sin theta + cos theta + sin theta is equal to 2

Answer 1

Answer:

L. H. S =R. H. S

Step-by-step explanation:

L. H. S

=(cos theta - sin theta) + (cos theta + sin theta)

Squaring,

=(cos theta - sin theta)^2 + (cos theta + sin theta)^2

=(cos ^2 theta - 2*cos theta *sin theta +sin^2 theta) + (cos ^2 theta +2*cos theta *sin theta +sin^2 theta)

= cos ^2 theta - 2*cos theta *sin theta +sin^2 theta + cos ^2 theta + 2*cos theta *sin theta +sin^2 theta

Now 2*cos theta *sin theta cancels,

=(cos ^2 theta +sin^2 theta) +(cos ^2 theta +sin^2 theta)

=1+1

=2

Answer 2

Hey mate,.....the other answer given is also very much crct but this is an another method for more and better conceptual understanding.....

Thanq☺️

Pls mark as branliest if it helped u